Patent Application
20060213137
1. Field of the Invention
The present invention relates generally to construction materials and more particularly to a reinforced decorative composite material that includes a top layer of decorative material, such as a high-pressure laminate, but could also be made of other material(s), such as paper, film, wood, or metal, and a stiffener core, such as fiber-reinforced thermoplastic, and, if desired, a bottom or backing layer, such as paper, secured together, and to the manufacture of such a composite sandwich material.
2. Description of Related Art
High pressure laminate (“HPL”) materials have been manufactured and sold for many years, and are familiar to many from their wide-spread use in kitchens and areas requiring very durable and decorative surface attributes. Such laminates are typically made of layers of paper impregnated with resin, compressed in a press or the like and heated to produce the desired laminate. One layer of paper may have a decorative pattern that remains visible in the finished product. The exact types of paper and of resins used, as well as the pressures, equipment and temperatures used, and the precise order of steps, are well known to those in the art. Typically, five to seven layers of paper may be incorporated in such a laminate material. A great variety of products of this type are commercially available from the Formica Corporation, under the trademark Formica, owned by that company. Examples of techniques and materials used in the manufacture of such laminates can be found in U.S. Pat. No. 5,558,906, assigned on its face to Formica Technology Inc., the entire disclosure of which is incorporated herein by reference.
HPL products, however, are generally brittle enough that they must be mounted on a layer of wood or other material of sufficient strength and rigidity, for use in the kitchen, and on any horizontal surface. Vertical surface applications of HPLs can be enhanced by a pre-laminated panel with the HPL as the outward side. A primary application of such a panel will likely be vertical wall surfaces, where drywall is a common substrate.
It is desirable to be able to use HPL products in environments where the product will be exposed to relatively high levels of wear and tear, moisture, and mechanical loads, without the need to mount the HPL on a mechanically strong layer of wood or other materials. For example, it would be desirable to be able to use decorative materials like HPL products in vertical wall applications in schools, hospitals, restaurants and other public areas that are subject to large amounts of traffic, and where conventional HPL cannot easily be used.
U.S. Patent Application Publication No. 2003/0157850 A1, the entire content of which is incorporated herein by reference, discloses that one of the solutions for overcoming the above problems with regard to HPL panels is, for example, to use a reinforced composite material that includes a laminate panel, a strengthening panel that has a reinforcement embedded therein, and a layer of adhesive disposed between the laminate panel and the strengthening panel to adhere the laminate panel and the strengthening panel together. The reinforcement in the strengthening panel may be fiberglass fibers, randomly oriented, or it may be provided in the form of a mesh or the like. In either case, the strengthening panel is made with a thermoset type resin (preferably a plastic (polymeric) material of the type known as fiberglass reinforced polyester).
U.S. patent application Ser. No. 10/360,785, the entire disclosure of which is also incorporated herein by reference, discloses an alternative structure. Specifically, it discloses combining a decorative layer, a strengthening panel that includes a reinforcement embedded therein, and a suitable means of securing the decorative layer and the strengthening panel together permanently. This securing function is achieved by a direct thermal fusion (or thermofusion) of the decorative layer and the strengthening panel, although one or more additional materials may also be present between the decorative layer and the strengthening panel. The reinforcement in the strengthening panel may be fiberglass fibers, randomly oriented, or it may be provided in the form of a mesh or the like. In either case, the strengthening panel is preferably a plastic (polymeric) material of the type known as fiberglass reinforced polyester.
Nonetheless, while the above-mentioned applications solve prior art problems, there is still a need to provide greater improvements. For example, the composite material disclosed in U.S. Patent Application Publication No. 2003/0157850 A1, requires an adhesive to combine the decorative layer and the strengthening panel. While U.S. patent application Ser. No. 10/360,785 eliminates the need for an adhesive material, direct fusion of two different types of polymers requires the application of high pressure. Also, in both of these documents, an additional process step would be required to achieve any possibility of providing the back of the selected strengthening panel with a different functionality.
Accordingly, one object of the present invention is to provide a material that will have the aesthetic qualities of HPL, can be easily installed on vertical surfaces, and is less expensive to manufacture, more versatile, or both, than the materials disclosed in U.S. Patent Application Publication No. 2003/0157850 A1 and in U.S. patent application Ser. No. 10/360,785, or other panels. It is also an object to provide such a material that will have sufficient mechanical strength for use in situations where conventional HPL products might not otherwise be usable, such as wall panel applications, without a substantial structural substrate.
The present invention provides a panel that is installer-friendly and combines the custom color/pattern flexibility of decorative paper or an HPL face with a water-proof, dimensionally stable, user-friendly core and optionally a bottom or backing layer for enhanced adhesion to glues used to install the panel. Further, this composite panel enhances the impact resistance and moisture resistance of known available decorative vertical wall panels. The subject panel will allow installation of an HPL vertical surface in a most expeditious manner saving labor costs in drywall preparation, and actual installation time of the panel, when compared to applying HPL on a drywall, which is usually accomplished by first mounting the HPL on thick wood.
These objects are met by the present invention, one embodiment of which is a reinforced composite material that comprises a decorative layer and a stiffener core that includes a reinforcement embedded therein, which are fused together by thermoplastic in the core. The stiffener core may include a reinforced thermoplastic layer and, if desired, various layers of a wide range of stiffening materials. Preferably, the reinforcement in the stiffener core matrix comprises, but is not limited to, various lengths of fiberglass fibers, continuous fiberglass mat, spun blown fiberglass fibers randomly oriented, or oriented in layers at different angles. The reinforcement may also be provided in the form of a woven reinforcement or the like. Moreover, the reinforcement, if continuous, can be either continuous-strand (i.e., random), or oriented in various directions, such as in layers oriented in different directions. The reinforcement may also be provided in the form of a woven or continuous and/or discontinuous (which again could be oriented or random) reinforcement or the like. Other types of reinforcement fibers might include, but are not limited to, various forms of carbon fiber, aramid fiber, and polyamide fiber. In either case, the stiffener core comprises a thermoplastic material such that the decorative layer can be thermally fused to the stiffener core via the thermoplastic fusing action of heating and subsequently cooling the stiffener core in the presence of the decorative layer.
The decorative layer is contemplated to be aesthetically acceptable, as it is typically visible in the final composite product.
Another embodiment also meeting the objects of the present invention is a composite material, which includes a bottom or backing layer that is thermally fused to the stiffening core on the opposite side to the decorative layer. The presence of the bottom or backing layer improves the ability of the composite to be applied to various surfaces.
The thicknesses of the layers may be selected according to need, but as examples, the decorative layer may be made from, typically, one layer of paper, or any decorative layer material (although greater numbers of layers are within the scope of the invention), either impregnated with resin or not and fused with the stiffener core and, if desired, with an optional backing layer by treatment at a temperature and pressure for a sufficiently long period of time to result in the permanent fusion of the various component layers. The stiffener core may, for example, be 0.030, 0.060 or 0.090 inch thick, although the invention is not limited to these specific numbers of layer combinations and thicknesses.
One aspect of the present invention involves reducing the weight of the reinforced composite material, by using a small number of sheets or layers of paper in the decorative layer, for example, preferably one, rather than the much larger numbers typically used in existing HPL products (often five to seven layers).
The present invention also provides a method for the production of such a material, in which there are provided a decorative layer, a stiffener core having an embedded reinforcement therein and, if desired, an optional backing layer. Then, the decorative layer and the backing layer, if present, are permanently secured to the stiffener core by direct thermoplastic fusion, which is effected by heating the decorative layer, the stiffener core, and, if provided, the bottom or backing layer, while subjecting them to pressure. In the absence of the backing layer, the decorative layer may be fused with the stiffener core in the same manner.
These and other objects, features and advantages of the present invention will be more fully apparent from a consideration of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.
a and 2b are details showing two varieties of fiber reinforced thermoplastic that may be used in the embodiment shown in
One of the most important features of the present invention is that the stiffener core contains a thermoplastic material, which allows this panel to be thermofused with a decorative layer and, if desired, a bottom or backing layer, without the need for an adhesive component or increased pressure due to the thermoplastic properties of the stiffener core.
Prior reinforced decorative composite material panels, such as those disclosed in U.S. Patent Application Publication No. 2003/0157850 A1 and U.S. patent application Ser. No. 10/360,785, use a fiber reinforced thermoset (e.g., polyester) substrate. Thermoset plastics, once their molecules are “cured” or “crosslinked”, are not able to be melted and/or reformed, nor can they adhere to other materials in and by themselves.
The present invention uses a reinforced thermoplastic material (e.g., fiber reinforced polypropylene). Thermoplastic molecules are lined up side by side. When heated, they become active and spread apart (melt, or the thermoplastic “flows”). When cooled, they close up together once again and become firm. It is during this thermoplastic “flow” process that the plastic will mechanically stick to another surface when it is subsequently cooled when held in proximity to that surface.
The thermoplastic portion of the reinforced thermoplastic melts at various temperatures, depending on the type of thermoplastic used. For example, polypropylene begins to melt at around 160-170° C. The melted thermoplastic, under low pressure in order to hold it in proximity to the other surfaces, flows to the backside of the decorative surface material and the surface and to both sides of any material inserted into the middle of the composite or on the back of the composite. At the same time, the melted plastic layers are fused together in a matter of minutes, forming, either alone or in conjunction with other materials inserted into, or on either side of, the composite, a stiffener core. When the thermoplastic is cooled, a product is formed in which all of the materials of the composite are physically fused together.
A decorative wall panel can be made by using a decorative finish like that of an HPL, or any decorative finish in which that finish is thermofused with a reinforced thermoplastic stiffener core comprised of (i) at least one layer of reinforced thermoplastic fused together in the process and/or (ii) a combination of reinforced thermoplastic layer(s) with various layers of a wide range of stiffening materials, such as, but not limited to, structural and flexible thermoplastic or thermoset open or closed cell foam, various plastic or metal honeycomb structures, sheet metal or wood, by applying heat and pressure to the combination of the various materials in a continuous low pressure press to cause the thermoplastic to melt (flow). More than one thermoplastic layer may be included when forming the stiffener core. The additional layers are not necessarily reinforced. Also, the thermoplastic materials in the different layers may differ from each other.
During the thermoplastic “flow,” the plastic comes in contact with the various surfaces and wets out the surfaces. The materials in the panel are integrated by commingling with the melted plastic. The additional various materials can improve the functionality of the finished product, for example, by providing additional stiffness and/or insulation.
The interaction of the thermoplastic material with the decorative layer is not limited to any specific form, so long as thermofusion is achieved. For example, the decorative layer may be substantially or totally impregnated with the thermoplastic material. Alternatively, it is contemplated that this layer may be substantially or completely not impregnated with the thermoplastic material.
The first preferred embodiment of the present invention is a reinforced composite material 10 having three portions 12, 14 and 16, as shown in
The types of paper that may be used in the decorative layer include all those types suitable for use in various laminates, and saturated papers typically used in thermofusing operations. In general, one layer of paper may have a decorative pattern on the side facing away from the stiffener core, so as to be visible in the finished product.
Also, while any type of thermoplastic resin suitable for the purpose can be used as a stiffener core material within the scope of the invention, such as, for example, polyethylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), acrylonitrate-butadiene-styrene (ABS), a polypropylene resin is preferred. These materials can be reinforced with fiberglass, in the form of random chopped, woven, spun blown, or continuous direction fibers. For ease in forming the stiffener core, normally, one of these thermoplastic materials will be used. However, it is within the scope of the present invention to use a combination of two or more such materials.
While it is preferred to use a sheet of fiber reinforced thermoplastic material for the stiffener core, it is also possible to use other types of reinforced thermoplastics. The reinforcement may comprise continuous and/or discontinuous fibers. Moreover, the reinforcement, if continuous, can be either continuous-strand (i.e., random), or oriented in various directions, such as in layers oriented in different directions. The reinforcement may also be provided in the form of a woven or continuous and/or discontinuous (which again could be oriented or random) reinforcement or the like.
For example, a thermoplastic 14 having reinforcing material in the form of a mesh or woven 18, rather than in the form of randomly-oriented fiberglass 18, as in fiber reinforced thermoplastics, forms a second preferred embodiment of the invention.
Thermoplastics are most often olefin-based compounds and have little affinity to typical glues or other materials generally used for applying panels to wall surfaces. Therefore, a backing layer, such as paper or non-woven materials (fiberglass, polyester or a fiber scrim), can be applied to the underside of the combination to provide a panel backside that is receptive to typical adhesives used to apply the panels.
Alternatively, or in conjunction with the use of the backing layer to improve the affinity of the composite to other materials, a portion of the reinforcement may not be completely embedded in the thermoplastic material, protruding from the surface of the stiffener core that faces away from the decorative layer. Preferably, this protruding portion is not completely coated with the thermoplastic material. More preferably, this portion is substantially not coated with the thermoplastic material.
A preferred method of manufacturing the composite material shown in
Preferably, the materials are fed to continuous belts 4a and 4b, which rotate in the machine direction via rollers 8 to convey the materials into the consolidation area 9. The conveyor belts 4a and 4b preferably also apply a constant low pressure to keep the layers of materials in contact with each other throughout the consolidation process. The belts feed the combination of materials to the heaters 5, which drive heat into the materials and melt (or flow) the thermoplastic. After the layers pass through the heaters 6, they are fed to chillers 6 to cool the thermoplastic back to a “solid” form, mechanically adhering the layers. Thus, the finished, layered consolidated product is formed.
The thicknesses of the layers of the light-weight reinforced composite material may be selected according to need. For example, the decorative layer may be formed from one to three layers of paper, although more may be used if desired. The fewer that are used, however, the greater the benefit that will be obtained, as the smaller number of layers of paper will result in lower overall cost of the finished product. The stiffener substrate may be 0.030, 0.060 or 0.090 inch thick. The selection of the thickness may depend on a number of factors; one will, of course, be ensuring that the resultant product complies with any applicable fire rating or other codes applicable to the intended use of the product. Nonetheless, the invention is not limited to these specific thicknesses and combinations of thicknesses.
Again, while it is contemplated to effect thermoplastic fusion of the saturated paper to the stiffener core and, if desired, a backing layer, it is contemplated within the broad scope of the invention to include one or more additional materials in contact with the decorative layer, the core, and/or the optional backing layer. Various such materials include what are known as a gator ply and as a receptor coat (the latter might, for example, be used to compensate for irregularities of the stiffener core surface). Other materials, however, may also (or instead) be used without departing from the scope of the invention. Such materials may enhance the properties of the stiffener core, such as increase its insulation and stiffness properties.
These additional materials may be placed between the stiffener core and the decorative and/or backing layer, resulting in the stiffener core not being in contact with the decorative and/or backing layer along the entire surface of the core facing such layer. For example, glue may be applied to a part of the interface to enhance adhesion of the layers. Since the stiffener core is thermoplastic, the combination of all layers in accordance with the present invention can be conducted simultaneously.
The decorative layer in accordance with the present invention is contemplated to be aesthetically acceptable, because it is typically visible in the final product. This decorative layer, however, is not necessarily a printed or any other pattern. The decorative layer may be pre-assembled or even a commercially available material (e.g., high or low pressure laminate), which is then combined with the stiffener core and/or the optional backing layer to form the composite material of the present invention.
While the present invention has been described in detail with reference to the currently-preferred embodiments, many modifications and variations of those embodiments will now be apparent to those skilled in the art. Accordingly, the scope of the invention is not to be limited by the details of the foregoing detailed description, but only by the terms of the appended claims.
