FIRE-RETARDANT-TREATED WOOD COMPOSITE PANELS FOR EXTERIOR APPLICATIONS OR WEATHER EXPOSURE DURING CONSTRUCTIONS

Abstract

A multi-layer fire-resistance treatment (FRT) panel for use as structural sheathing. The wood structural panel may be OSB or plywood, coated or treated during the manufacturing process with a product that provides fire resistance. The treatment may be integrated with the material forming the wood structural panel, or may be a coating layer applied to the mat or mat layer. A burn-through layer also may be applied. A protective layer comprising a resin-impregnated paper overlay may be applied on one or both sides of the panel.

Claims

1. A method of producing a fire-resistant integrated structural sheathing panel, comprising the steps of: producing wood strands, flakes or chips; treating some or all of the wood strands, flakes or chips with fire-resistant chemicals or additives, or both; forming, in a production line, a mat with one or more layers from said treated wood strands, flakes or chips, said mat comprising a top surface and bottom surface; applying a first burn-through resistant coating layer to the top surface of the mat; applying a first resin-impregnated paper overlay to an upper side of the burn-through resistant coating layer opposite the top surface of the mat; and applying, in said production line using a production press, heat and pressure to the mat, burn-through resistant coating and resin-impregnated paper overlay to form a board with a first surface and a second surface, wherein the first surface comprises the first burn-through resistant coating layer and the first paper overlay.

2. The method of claim 1, further comprising the steps of: applying a second resin-impregnated paper overlay to the bottom surface of the mat.

3. The method of claim 1, wherein the first resin-impregnated paper overlay is configured to prevent leaching of the fire-resistant chemicals or additives from the board.

4. The method of claim 2, wherein the second resin-impregnated paper overlay is configured to prevent leaching of the fire-resistant chemicals or additives from the board.

5. The method of claim 1, wherein the fire-resistant chemicals or additives comprise one or more of a phosphate compound, a boron compound, aluminum hydrate, or amino resins.

6. The method of claim 1, wherein the burn-through resistant coating comprises one or more of a non-combustible magnesium oxide coating, non-combustible fiberglass reinforced magnesium oxide coating, or intumescent coating.

7. The method of claim 1, wherein the board is an oriented-strand board.

8. A sheathing panel produced according to the method of claim 1.

9. A method of producing a fire-resistant integrated structural sheathing panel, comprising the steps of: producing wood strands, flakes or chips; treating some or all of the wood strands, flakes or chips with chemicals or additives, or both; forming, in a production line, a mat with one or more layers from said treated wood strands, flakes or chips, said mat comprising a top surface and bottom surface; applying a first fire-resistant coating layer to the top surface of the mat; applying a first burn-through resistant coating layer over the first fire-resistant coating on the top surface of the mat; applying a first resin-impregnated paper overlay over the burn-through resistant coating layer on the top surface of the mat; and applying, in said production line using a production press, heat and pressure to the mat, first fire-resistant coating layer, first burn-through resistant coating and first resin-impregnated paper overlay to form a board with a first surface and a second surface, wherein the first surface comprises the first fire-resistant coating layer, the first burn-through resistant coating layer and the first paper overlay.

10. The method of claim 9, further comprising the steps of: applying a second resin-impregnated paper overlay to the bottom surface of the mat.

11. The method of claim 9, wherein the first resin-impregnated paper overlay is configured to prevent leaching of the fire-resistant chemicals or additives from the board.

12. The method of claim 10, wherein the second resin-impregnated paper overlay is configured to prevent leaching of the fire-resistant chemicals or additives from the board.

13. The method of claim 9, wherein the first fire resistant coating comprises one or more of a non-combustible magnesium oxide coating, non-combustible fiberglass reinforced magnesium oxide coating, or intumescent coating

14. The method of claim 9, wherein the first burn-through resistant layer comprises one or more of a non-combustible magnesium oxide coating, non-combustible fiberglass reinforced magnesium oxide coating, or intumescent coating.

15. The method of claim 9, wherein the board is an oriented-strand board.

16. A sheathing panel produced according to the method of claim 9.

17. A method of producing a fire-resistant integrated structural sheathing panel, comprising the steps of: producing wood strands, flakes or chips; treating some or all of the wood strands, flakes or chips with fire-resistant chemicals or additives, or both; forming, in a production line, a mat with one or more layers from said treated wood strands, flakes or chips, said mat comprising a top surface and bottom surface; applying a first weather-resistant overlay to an upper side of the burn-through resistant coating layer opposite the top surface of the mat; and applying, in said production line using a production press, heat and pressure to the mat, burn-through resistant coating and resin-impregnated paper overlay to form a board with a first surface and a second surface, wherein the first surface comprises the first burn-through resistant coating layer and the first weather-resistant overlay.

18. The method of claim 17, further comprising the step of applying a first burn-through resistant coating layer to the top surface of the mat.

19. The method of claim 18, wherein the first weather-resistant overlay is a resin-impregnated paper overlay.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 shows a cross-section of a FRT panel in accordance with the present invention.

[0011] FIG. 2 shows a cross-section of another FRT panel in accordance with the present invention.

BRIEF DESCRIPTION OF INVENTION

[0012] In various exemplary embodiments, the present invention comprises a multi-layer FRT panel 2 for use as structural sheathing. The multi-layer panel comprises a wood structural panel 10, such as OSB or plywood, coated or treated with a product that provides fire resistance. The treatment may be integrated 12 with the material forming the wood structural panel (as seen in FIG. 2), or may be a coating layer 20 applied to the mat or mat layer after being formed (as seen in FIG. 1). In several embodiments, the treatment gives it Fire Resistant (FR) characteristics (for use in a hour fire-resistance-rated assemblies, or where FRT wood is required by building codes).

[0013] At least one sheet of a weather-resistant overlay, e.g., a resin-impregnated paper overlay, 30 is placed as a protective layer on the top of the mat before the mat and overlay are pressed to form a FRT composite panel of the present invention. At least one sheet of overlay may also be placed underneath 32 the mat being formed, and in some embodiments, sheets of overlay are located both underneath and over the mat, thereby providing an overlay (protective layer) on both faces of the FRT composite panel.

[0014] After pressing, the FRT panel may then be primed and/or coated with a water-resistant coating. Edge sealant may be applied to the edges 40 of the panels. In an alternative embodiment, a weather-resistant or protective sheet or layer may be applied to the FRT panel in a secondary manufacturing process.

[0015] The overlay protective layer(s), as described above, helps prevent or reduce FRT chemical loss by limiting or preventing the core FRT layer(s) (in the mat or on the surface of the mat) from being exposed to water and/or weather, and by keeping or limiting FRT chemicals from leaching out of the panel.

[0016] The multi-layer panel provides a building-code-compliant product that provides structural performance and fire resistance characteristics for use in wall and roof applications that require a fire resistance performance, such as residential, single- or multi-family, and commercial construction. In one embodiment, the panel comprises an OSB sheathing panel with a FR treatment applied to the panel. The FR treatment may be applied one side of the panel, or in some embodiments, both sides of the panel. The FR treatment may comprise one or more of the following: non-combustible magnesium oxide coating; non-combustible fiberglass reinforced magnesium oxide coating; fire-resistant/resistance wood structural panel; intumescent coating; integral or surface applied chemical treatment; or combinations thereof. This FR treatment allows the panel to be used in approved hour fire-resistance-rated assemblies, or where FRT wood is required by building codes. As an alternative to FR-treated OSB sheathing panels, sheathing panels also may comprise glass mat sheathing or FRT plywood. Examples of FR-treated panels are disclosed in U.S. patent application Ser. No. 15/365,731, filed Nov. 13, 2016, and U.S. patent application Ser. No. 17/491,367, filed Sep. 30, 2021, both of which are incorporated herein in their entireties by specific reference for all purposes.

[0017] In a further exemplary embodiment, a burn-through resistant coating is applied on the surface of the FRT panel to provide burn-through resistance to addition to the flame spread resistance provided by the FRT, thereby enhancing overall performance in a fire event. The burn-through coating also helps reduce FRT leaching from the panel. The burn-through resistant coating comprises one or more of the following: non-combustible magnesium oxide coating; non-combustible fiberglass reinforced magnesium oxide coating; coating specially formulated with cement, vermiculate or other similar inorganic fire protective material; surface applied chemical treatment; and/or intumescent coating; or combinations thereof.

[0018] In contrast to the prior art, where a WRB system is separately applied to sheathing panels at the job site after installation, the present invention applies a WRB to the FR panel at the manufacturing facility, prior to shipping or installation at a job site, thereby avoiding the problems noted above with regard to prior art systems. The present invention can also be used in other exterior applications (such as, but not limited to, sidings).

[0019] Branding or markings, if any, to be applied to the panel are then applied or printed on the coated surface of the desired face, such as by using a digital printer or other stamping process. This marking also may be performed in the manufacturing line.

[0020] Thus, it should be understood that the embodiments and examples described herein have been chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited for particular uses contemplated. Even though specific embodiments of this invention have been described, they are not to be taken as exhaustive. There are several variations that will be apparent to those skilled in the art.