Static structures (e.g. – buildings) – Composite prefabricated panel including adjunctive means – Sandwich or hollow with sheet-like facing members
Reexamination Certificate
2001-07-30
2004-03-30
Ramirez, Ramon O. (Department: 3632)
Static structures (e.g., buildings)
Composite prefabricated panel including adjunctive means
Sandwich or hollow with sheet-like facing members
C052S783190
Reexamination Certificate
active
06711872
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to building materials. More specifically, the invention relates to a lightweight panel construction that is suitable as a substitute or alternative for conventional gypsum wallboard.
2. Prior Art
The interior framing of residential and commercial buildings is typically covered or finished with sheets of gypsum board, commonly referred to as drywall, wallboard or Sheetrock® (trademark of U.S. Gypsum Company). Conventional gypsum wallboard has a gypsum plaster core faced with sheets of paper, and normally is made in standard size panels with dimensions of 4×8, 4×12 or 4×16 feet, and thicknesses ranging from ⅜ inch up to ¾ inch, although thicknesses as little as ¼ inch can be obtained by special order for specialized use.
Considerable transportation costs, and difficulty in handling and installation are associated with conventional gypsum wallboard because of its density and weight. Moreover, gypsum wallboard is susceptible to moisture damage, and is easily dented or broken if struck near the edges or corners. Further, relatively expensive landfill costs are associated with disposal of conventional gypsum board.
Alternatives to conventional gypsum wallboard have been proposed, including wood particle board, and lightweight materials such as paper fiber, composites of synthetic materials, and/or honeycomb reinforcing structures faced with various materials, including plaster or conventional sheets of gypsum board.
U.S. Pat. No. 3,106,503, for example, discloses a composite wallboard having a paper honeycomb core which can be faced on one or both sides with commercially available conventional sheets of gypsum board. The principal object of this patent is to provide a structural panel that can withstand direct contact with flame, and which may be moisture resistant. Further, a stated object is also to provide a lightweight structural panel that has superior qualities of rigidity and strength. However, commercially available sheets of gypsum board having conventional thickness, i.e., from ⅜ inch up to ¾ inch, are applied to the honeycomb core. The panels described in this patent are therefore relatively heavy and hard to handle in that they still incorporate sheets of gypsum board having conventional thickness, and the composite panel appears to have a total thickness substantially greater than the thickness of conventional gypsum board. Further, manufacture of the panels described in this patent is relatively complicated and expensive.
U.S. Pat. No. 3,170,827 discloses a method of making an insulation panel having facing sheets of asbestos cement board separated by approximately six inches of polyurethane foam reinforced with honeycomb paper. In making the panel, a layer of foam-forming chemicals is deposited on a bottom facing sheet, a honeycomb structure is pressed into the chemical layer into bonding relationship with the bottom facing sheet, the foam is expanded, and a top facing sheet is placed on top of the structure, in contact with the expanded foam, which bonds the components together.
U.S. Pat. No. 3,246,058 discloses a method for producing reinforced foam laminate structures, wherein a reinforcement member, e.g., corrugated material, is fed between two continuously supplied spaced sheets of facing material, at least one of which has been coated with an organic foam material, and the foam is expanded to fill the space and bond the components together.
U.S Pat. No. 3,249,659 discloses a method of making structural panels useful as walls, partitions, doors, truck bodies and the like, wherein a core is interposed between facing sheets and partially filled with a foamed plastic to form an air space therein. In particular, a layer of foam-forming mixture is applied to the inner surfaces of the facing sheets, a reinforcing member is inserted between the sheets, and the layers of foam-forming mixture are expanded toward one another but without merging. A structure analogous to an I-beam is thus formed.
U.S. Pat. No. 4,351,870 discloses a panel construction especially suitable for earthquake and fire resistance, and adapted for assembly of pre-fabricated components to form a building. The panel includes one or more layers of strength-increasing material separated by lower strength bulk-producing layers which may comprise foamed plastic or foam rubber materials. Facing sheets such as wood veneer, plastic simulated wood veneer, wallpaper finish, brick, tile, or plaster may be used to obtain a desired appearance.
U.S. Pat. No. 4,917,742 discloses a method of making lightweight building panels having a foam-filled honeycomb core faced with fiberglass-reinforced plastic sheets.
U.S. Pat. No. 5,309,690 discloses a lightweight composite panel intended as a substitute for gypsum board. The panel comprises a cellular core filled with an inorganic insulating material and a material which releases water at elevated temperatures, and first and second sheets such as corrugated cardboard bonded to opposite sides of the core.
U.S. Pat. No. 5,338,594 discloses a lightweight insulation and structural material for building and aerospace industries, wherein a honeycomb structure is filled with a polycyanurate foam. The foam is expanded in the honeycomb cells while contained by pressure plates above and below the cells.
U.S. Pat. No. 5,679,433 discloses a non-combustible wall decorating panel having a honeycomb core and a metal foil facing sheet.
Although the prior art discloses a variety of panels, some of which have good strength-to-weight ratios, including panels suitable for use in the building industry, it does not disclose any lightweight and tough panel intended as a substitute for conventional gypsum board wall panels, wherein the substitute panel has the same surface characteristics as conventional gypsum board panels, i.e., it has a surface veneer of paper-covered gypsum plaster, and preferably has the same dimensional relationships, whereby the panel may be installed and finished using conventional techniques and equipment.
Accordingly, there is need for a panel that has the same surface characteristics as a conventional gypsum board, and has the same dimensional relationships, but is substantially lighter in weight while at the same time possessing superior toughness.
SUMMARY OF THE INVENTION
The invention is a composite panel for use in place of conventional gypsum board panels, and that has the same surface characteristics and preferably the same dimensional relationships as a conventional gypsum board panel, but is significantly lighter in weight while at the same time possessing superior toughness.
The panel of the invention is an improvement over conventional drywall or gypsum board primarily because of its greatly reduced density, which results in a weight reduction of sixty or percent or greater, and the benefits associated with this reduced density. These benefits include reduced transportation costs and requirements, reduced labor for handling and installation, less dust and debris when working with the panel, improved workability and elimination or reduction of landfill fees required for disposal, and potentially a reduction of structural members that would otherwise be required in a building simply to support the considerable weight of conventional gypsum board.
The panel of the invention comprises an open cell reinforcing core structure faced with a thin gypsum board veneer, and has a greatly improved strength-to-weight ratio compared with conventional gypsum board panels, especially when it employs a foam-filled core construction, being synergistically stronger than either the open cell core structure or the gypsum board alone.
One open cell core construction suitable for use in the invention is the Hexacomb
tm
packaging material made by Pactive Corporation (formerly Tenneco). This packaging material is a paper honeycomb structure, and in one embodiment comprises strips of 33 lb. liner glued together at contact lines running in the mach
International Paper Company
Lambert Dennis H.
Ramirez Ramon O.
Szumny Jon
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