Interface layer for improved engineered wood products

Abstract

A multi-layered engineered wood-based siding, cladding or panel with an interface layer disposed between the main strand matrix layers and one or more additional layers. The interface layer can be an adhesive web, or adhesive film, or adhesive net. The adhesive web / film / net can serve as a fines interface layer to minimize telegraphing and provide an improved surface appearance. The interface layer can be applied to the surface of the strand matrix or mat prior to application of the fines layer. The interface layer can be disposed between the strand matrix and the fines layer to prevent the loss of fines into the strand matrix. The interface layer can be disposed between any of the layers of the multi-layered engineered wood product to promote adhesion between adjacent layers, impart fire resistant, impart mold and mildew resistance, or increase the dimensional stability of the wood product.

Description

[0001] INTERFACE LAYER FOR IMPROVED ENGINEERED WOOD PRODUCTS

[0002] All patents, patent applications, and publications cited herein are hereby incorporated by reference in their entirety. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled therein as of the date of the invention described and claimed herein.

[0003] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

[0004] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 760,030, entitled “INTERFACE LAYER FOR IMPROVED ENGINEERED WOOD PRODUCTS,” filed February 18, 2025, the contents of which is incorporated herein by reference in its entirety.

[0005] FIELD OF INVENTION

[0006] This invention relates to a system and process for producing a multi-layered engineered wood-based siding, cladding or panel (e.g., manufactured with wood veneer, strands or fibers) with an interface layer between at least two layers of the engineered wood product. In specific embodiments, the interface layer is a fines interface layer disposedadjacent to a fines layer to minimize telegraphing and improve the appearance of the final product.

[0007] BACKGROUND

[0008] Engineered wood products (such as OSB, LSL, LVL, or plywood) typically are produced by various primary (and sometimes secondary) pressing processes. Examples of such processes are in U.S. Pat. Nos. 6,461,743; 5,718,786; 5,525,394; 5,470,631; and 5,425,976; and U.S. Patent Application No. 15 / 803,771; all of which are incorporated herein in their entireties by specific reference for all purposes.

[0009] The nature of the engineered wood manufacturing process and the impact of moisture exposure and temperature changes over time could result in inherent sub-surface and surface defects or imperfections. Sub-surface defects often result in visible defects or imperfections on the surface (commonly referred to as “telegraphing”). Deeply or aggressively embossed or textured surfaces often can distract the eye from noticing these imperfections, but smooth (non-embossed or minimally embossed) surfaces are more susceptible to having this telegraphing become noticeable, especially under critical light conditions. This is a particular problem with engineered wood based smooth surface siding or cladding when installed on a building, where varying light conditions and viewing angles make undesirable surface imperfections noticeable.

[0010] During the manufacturing of strand-based engineered wood products, several formers (typically four, five or six) with orientation heads apply strands in multiple layers to a continuously moving conveyor belt. Each forming head will inevitably have a varying number of strands layered on top of one another to form an intertwined layer of stands. Aseach forming head operates independently from one another, the variation of the number of strands that is ultimately achieved in any one location in the final layered mat contains the combined variation of all the forming heads. This variation is advantageous in the pressing process as it helps to better facilitate the escape of volatilized water that is necessary to mold the strands together under high heat and pressure during the pressing process, resulting in a structural panel product. However, when using such products in an aesthetic application, such as exterior cladding, this variation in the number of strands that comprise the thickness of the product creates some challenges. As strands are still relatively large particles of wood, as compared to the fines used in other wood composites such as MDF (medium density fiberboard) and particleboard, an engineered wood product comprised of strands is still subject to the inherent properties of the wood itself.

[0011] One such property is the change in dimension in response to a change in moisture content. All wood species expand and contract at various levels in response to changing moisture conditions. This is largely due to the transport systems within the wood cell structure itself which are intended to carry water through a living tree. As strands are still large pieces of wood, these transport systems largely remain intact within each strand. With a varying number of strands within each location across the panel, and each strand responding with a change in dimension as moisture conditions change within the panel, there is the potential for differential thickness swell across the surface of any panel. In products that are used in aesthetic applications, such as exterior cladding, even subtle (i.e., less than 0.002”) differences in thickness can be seen by the naked eye in critical light conditions. Therefore, when utilizing a strand-based product in these aesthetic applications, there exists a need to effectively control this differential movement or strands frombecoming visible in addition to the other inherent surface imperfections that occur in a strand-based product manufacturing process.

[0012] SUMMARY OF INVENTION

[0013] This disclosure relates to a method or process for producing an engineered woodbased siding, cladding or panel (e.g., manufactured with wood veneer, strands or fibers) with an interface layer between at least two layers of the wood-based product. In one embodiment, the interface layer is a fines interface layer between the main strand layers and the fines layer configured to minimize telegraphing and provide an improved surface appearance.

[0014] In one aspect, the present disclosure relates to an improved method of producing a multi-layered engineered wood product. In various embodiments, the method comprises: forming at least one layer of the multi-layered engineered wood product, said at least one layer comprising a top surface. The method can further comprise applying an interface layer with a latent adhesive property on the top surface of at least one layer of the multilayered engineered wood product. In embodiments, the interface layer comprises a web, a film, a net, or a combination thereof. The interface layer can comprise an upper surface opposite the layer to which the interface layer is applied. In embodiments, the method further comprises consolidating and bonding interface layer and the at least one layer together using heat, pressure, or a combination thereof.

[0015] In embodiments, the method comprises forming a fines layer on the upper surface of the interface layer, wherein the fines layer comprises a plurality of fines and the interface layer is configured to prevent the passage of at least a portion of the fines from the fines layer into the at least one layer. In embodiments, the at least one layer comprises a strandmatrix, and the interface layer is configured to prevent the passage of the majority of fines from the fines layer into the strand matrix. The interface layer can comprise a flexible material. In certain embodiments, the interface layer is a thermoplastic, thermoset, or pressure-sensitive material. The flexible material can be a synthetic or natural material.

[0016] In certain embodiments, the interface layer comprises polyester, polyamide, polyolefin, polypropylene, vinyl acetate, polystyrene, copolyimide, polytetrafluoroethylene, acrylic, polyurethane, epoxy, silicone, or any combination thereof. The interface layer can comprise a phenolic-based material. In some embodiments, the interface layer comprises a vegetable oil, a starch, another natural polymer, or any combination thereof

[0017] In embodiments, the interface layer partially or fully melts upon reaching an activation temperature during the step of consolidating and bonding.

[0018] The interface layer can comprise a material with a melting point between about 165 °F to about 450 °F.

[0019] In embodiments, the interface layer provides one or more of the following: fire resistance; fungal resistance; moisture resistance; and sound dampening.

[0020] In various embodiments, the presently disclosed method comprises applying an overlay on an upper surface of the fines layer opposite the interface layer.

[0021] In embodiments, the step of consolidating and bonding comprises application of heat and pressure using a hot press. In certain embodiments, the step of consolidating and bonding comprises application of pressure using a cold press. The step of consolidating and bonding can comprise application of microwaves with or without a heated platen. Inembodiments, the step of consolidating and bonding comprises application of super-heated steam.

[0022] In another aspect, the present disclosure relates to an engineered-wood product produced by any of the various methods disclosed herein. In embodiments, the engineered-wood product is an Oriented- Strand Board (OSB) plank, board or panel. The engineered-wood product can be siding, cladding or panel.

[0023] It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It also should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features that are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 shows a top partial view of a manufactured wood product with an interface layer (IL) between a preliminary multi-layered strand matrix and a functional fines layer (not to scale).

[0026] Figure 2 shows a partial side view of Fig. 1 (not to scale).Figure 3 shows a diagram of a non-limiting, exemplary method in accordance with the present disclosure.

[0027] Figure 4A shows a top perspective and exploded view of a multi-layered manufactured wood product with an IL under another embodiment (not to scale). The IL is shown between the overlay and the functional fines layer.

[0028] Figure 5 provides a top perspective and exploded view of a multi-layered manufactured wood product with an IL under yet another embodiment (not to scale). The IL is shown between the strand matrix and the functional fines layer.

[0029] Figure 6 shows a top perspective and exploded view of a multi-layered manufactured wood product with an IL under yet another embodiment (not to scale). The IL is shown between the strand matrix and the fines layer.

[0030] Figure 7 provides a top perspective and exploded view of a multi-layered manufactured wood product with two ILs under one embodiment (not to scale). A first IL is shown on a first surface of the strand matrix and a second IL is shown on a second surface of the strand matrix.

[0031] Figure 8 provides a top perspective and exploded view of a multi-layered manufactured wood product with two ILs under another embodiment (not to scale). A first IL is shown on a first side of functional filler and a second IL is shown on a second side of the functional filler.

[0032] Figure 9 shows a top perspective and exploded view of a multi-layered manufactured wood product with an IL under another embodiment (not to scale). The IL is shown between the overlay and the strand matrix.Figure 10 provides a top perspective and exploded view of a multi-layered manufactured wood product with two ILs under another embodiment (not to scale). A first IL is shown between a first side of a strand matrix and a first overlay and a second IL is shown between the second side of the strand matrix and a second overlay.

[0033] Figure 11 shows a top perspective and exploded view of a multi-layered manufactured wood product with a plurality of ILs under another embodiment (not to scale). A first IL is shown between a first overlay and a first functional filler layer; a second IL is shown between the first functional filler layer and a first side of a strand matrix; a third IL is shown between a second side of the strand matrix and a second functional filler layer; and a third IL is shown between the second functional filler layer and a second overlay.

[0034] Figure 12 shows a top perspective and exploded view of a multi-layered manufactured wood product with a plurality of ILs under another embodiment (not to scale). A first IL is shown between a first overlay and a first fines layer; a second IL is shown between the first fines layer and a first side of a strand matrix; a third IL is shown between a second fines layer and a second overlay.

[0035] Figure 13 provides a schematic view of a fines material being deposited on top of an IL during the manufacture of a multi-layered manufactured wood product.

[0036] DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The present disclosure may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, and it is therefore desired that the embodiments of the disclosure be considered in all aspects as illustrative and not restrictive. Any headings utilized in the description are for convenience only and no legal or limiting effect. Numerous objects, features, and advantages of the embodiments set forth herein will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings.

[0038] The singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification can mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” Wherever any of the phrases “for example,” “such as,” “including” and the like are used herein, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise. Similarly, “an example,” “exemplary” and the like are understood to be nonlimiting.

[0039] The term “substantially” allows for deviations from the descriptor that do not negatively impact the intended purpose. Descriptive terms are understood to be modified by the term “substantially” even if the word “substantially” is not explicitly recited. Therefore, for example, the phrase “wherein the lever extends vertically” means “wherein the lever extends substantially vertically” so long as a precise vertical arrangement is not necessary for the lever to perform its function.

[0040] The terms “comprising” and “including” and “having” and “involving” (and similarly “comprises,” “includes,” “has,” and “involves”) and the like are used interchangeably and have the same meaning. Specifically, each of the terms is definedconsistent with the common United States patent law definition of “comprising” and is therefore interpreted to be an open term meaning “at least the following,” and is also interpreted not to exclude additional features, limitations, aspects, etc. Thus, for example, “a process involving steps a, b, and c” means that the process includes at least steps a, b, and c. Wherever the terms “a” or “an” are used, “one or more” is understood, unless such interpretation is nonsensical in context.

[0041] As used herein the term “about” is used herein to mean approximately, roughly, around, or in the region of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” is used herein to modify a numerical value above and below the stated value by a variance of 20 percent up or down (higher or lower).

[0042] References in the specification to “one embodiment,” “an embodiment,” “an exemplary embodiment,” etc., indicates that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment may not necessarily include such feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0043] “Lignocellulose-based” or “lignocellulose-based” may be used interchangeably herein in reference to materials, products, or substances that are primarily composed of lignocellulosic materials or derived from lignocellulosic biomass. Lignocellulose is plantbiomass that comprises cellulose, hemicelluloses, and lignin, in which cellulose can refer to a natural polymer found in the cell walls of plants.

[0044] “Wood,” as used herein can refer to a lignocellulosic material that comprises cellulose fibers embedded in a carbohydrate-lignin matrix.

[0045] The term “fire-resistant,” as used herein, encompasses any type of fire barrier substance, such as fire retardants, flame retardants, and flame-resistant materials.

[0046] In various exemplary embodiments, the present invention comprises a method or process for producing an engineered wood-based siding, cladding, or panel 2 (e.g., manufactured with wood veneer, strands or fibers) with an interface layer (i.e., an interface layer between the any one or more layers of a multilayered wood product). In embodiments, the interface layer comprises a fines interface layer disposed between the main strand layers and the fines layer to minimize telegraphing and provide an improved surface appearance.

[0047] In embodiments, a “fines layer” can be applied to the surface of the multi-layer strand matrix or mat during the manufacturing process. The fines in the fines layers can comprise “wood flour” or small particles of wood, which can be a by-product from the strand processing. The functional fine layer can be added to minimize telegraphing of strands or flakes on the surface of the siding or finished product. However, a portion of the fines fall into open spaces or voids in the strand matrix, which reduces the effectiveness of the fines layer in resisting strand telegraphing.

[0048] In various exemplary embodiments, a “interface layer” (or IL) is applied between the surfaces of any one or more layers of a multi-layered wood product. The IL can comprise a fines interface layer that is applied to the surface of the strand matrix or matprior to application of the fines layer. In such embodiments, the IL sits between the strand matrix and the fines layer and prevents the loss of fines into the strand matrix. The IL can, thus keep the fines at the surface so they can effectively and efficiently function to prevent or eliminate strand telegraphing and provide a smooth finished surface for the product. Exemplary fines interface layers can be foundinUSl 1872720B2, US20240116212A1, and US20220412084 AL

[0049] The IL may comprise a fabric (such as, but not limited to, a woven or non-woven synthetic or natural material), specialty papers, resin-saturated or resin-impregnated papers, pulp mats, glue (adhesive) films, plastic films, minerals, or similar materials that can be used to separate any one or more layers in a multi-layered wood panel or product. The IL can comprise an adhesive net or film or web. The material used for the IL can be compatible with the particular manufacturing process, i.e., compatible with any adhesive, additives, heat and / or pressure that may be used. In some embodiments, for example, the manufacturing process comprises high temperatures and pressure. In several embodiments, the IL can be able to withstand high temperatures up to 230 degrees F. While in some embodiments the IL may be chosen to withstand high temperatures and pressure, in alternative embodiments the IL may be chosen so that the manufacturing process produces changes in the form or configuration of the IL material (e g., melting or flowing). Thus, for example, the IL material may comprise glass or glass-like material, a thermoplastic material, or any other binding material that partially or fully melts, flows and / or bonds (adheres) during the pressing process.In other embodiments, a stiffening material is added to the IL, so that the IL becomes stiffer and stronger during the pressing process and helps provide additional strength and stiffness to the final product itself.

[0050] In further exemplary embodiments, the IL material may be selected due to natural material properties, such as, but not limited to, adhesive properties, latent adhesive properties, fire resistance, fungal resistance, moisture / water resistance, sound dampening, or the like. Alternatively, or in addition, the IL may be treated or otherwise subject to an activation stimulus to provide or enhance such properties.

[0051] In certain embodiments, the IL comprises a mesh-like, fire-retardant adhesive web or net.

[0052] One exemplary approach for reducing the appearance of strands on the exterior surface of a finished strand matrix product is through the application of “fines layer” to the surface of the multi-layer strand matrix or mat during the manufacturing process. The “fines layer” can be comprised of “fines,” which can be material that predominantly comprises very small or “fine” particles. The fines layer can comprise biomass-based fines, microparticles, powder, micro-strands, any, and the like. In various embodiments, the term “fines” refers to small, fine particles that result from the crushing or processing of materials. The fines can comprise material that is a by-product or waste from another process or procedure. In certain embodiments, the fines in the fines layers comprise “wood flour” or small particles of wood, which can be a by-product from the strand processing. In another embodiment, the fines comprise coffee grounds.

[0053] In one exemplary embodiment, the functional fines layer is added to minimize telegraphing of strands or flakes on the surface of the siding or finished product. However,a portion of the fines fall into open spaces or voids in the strand matrix or any other layer of multi-layered engineered wood product, which reduces the effectiveness of the fines layer in resisting strand telegraphing.

[0054] The material used for fines can comprise particles that are less than about 10 mm in any dimension. In embodiments, the particles used for fines are less than about 6 mm in any dimension. The largest dimension of any one or mor particles used for fines can be about 2.0 mm. In certain embodiments, the fines particles are less than about 1.5 mm in any dimension. The largest dimension of any one or more fines particles can be about 1.0 mm, about 0.5 mm, about 0.25 mm, or about 0.1 mm.

[0055] In various exemplary embodiments, as seen in Figs. 1 and 2, an “interface layer” (or IL) 20 is applied to the surface of the strand matrix or mat (e.g., a preliminary multilayer strand matrix with proprietary alignment) 10 prior to application of the fines layer 30.

[0056] In one embodiment, the IL 20 sits between the strand matrix 10 and the fines layer (sometimes referred to as a functional fines layer) 30 and prevents the loss of fines into the strand matrix. The IL thus keeps the fines at the surface so they can effectively and efficiently function to prevent or eliminate strand telegraphing and provide a smooth finished surface for the product.

[0057] As shown in Figs 1-13, the IL 20 can be applied or disposed upon or between any one of more layers of a multi-layered manufactured wood product. In certain embodiments, the IL 20 is disposed upon any one or more layers between the strand matrix 10 and the overlay 40.

[0058] Figure 4 shows a top perspective and exploded view of a multi-layered manufactured wood product 201 that comprises a strand matrix 10, a fines layer 30, an IL20, and an overlay 40. As can be seen, in this embodiment, the fines layer 30 is applied directly onto at least one surface of the strand matrix 10, and the IL 20 is disposed between the fines layer 30 and the outer overlay 40.

[0059] Figure 5 provides a top perspective and exploded view of a multi-layered manufactured wood product 202 that comprises a strand matrix 10, a fines layer 30, an IL 20, and an overlay 40. In this embodiment, the IL 20 is applied over at least a portion of at least one surface of the strand matrix 10, and the fines layer 30 is applied over the IL 20 and under the overlay 40.

[0060] Figure 6 shows a top perspective and exploded view of a multi-layered manufactured wood product 203 that comprises two ILs 20, 22, two fines layers 30, 32 and two overlays 40, 42 that are symmetrically dispersed on each side of the strand matrix 10.

[0061] In this embodiment, the first fines layer 30 is disposed on a first surface 11 of the strand matrix 10, and the first IL 20 is disposed between the first fines layer 30 and the first overlay 40. The second fines layer 32 is disposed on th second surface 13 of the strand matrix 10, and the second IL 22 is disposed between the second fines layer 32 and the second overlay 42.

[0062] Figure 7 provides a top perspective and exploded view of a multi-layered manufactured wood product 204 with two ILs 20, 22 under an embodiment with asymmetric distribution of layers around the strand matrix 10. Briefly, in the Figure 7 embodiment, the strand matrix 10 is sandwiched between a first IL 20 and a second IL 22.

[0063] The first fines layer 30 is disposed between the first IL 20 and the first overlay 40. The second IL 22 is disposed on the second surface 13 of the strand matrix 10, and the second fines layer 32 is disposed between the second IL 22 and the second overlay 42.Figure 8 provides a top perspective and exploded view of a multi-layered manufactured wood product 205 with two ILs 20, 22, a functional fdler 50, and an overlay 40. A first IL 20 can be seen between the first side 51 of the functional filler 50 and the overlay 40, and the second IL 22 is shown between the strand matrix 10 and a second side 53 of functional filler 50.

[0064] Figure 9 shows a top perspective and exploded view of a multi-layered manufactured wood product 206 with an IL under another embodiment. The IL 20 is shown between the overlay 40 and the strand matrix 10. Thus, as can be seen in this Figure 9 embodiment 206, the IL 20 can be useful on in the absence of a fines layer to serve as an adhesive layer between two alternate layers of a manufactured wood product.

[0065] Figure 10 shows a top perspective and exploded view of a multi-layered manufactured wood product 207 that comprises two ILs 20, 22, and two overlays 40, 42 that are symmetrically dispersed on each side of the strand matrix 10. In this embodiment, the first IL 20 is disposed between a first surface 11 of the strand matrix 10 and the first overly 40, and the second IL 22 is disposed between a second surface 13 of the strand matrix 10, and the second overly 42 such that the strand matrix 10 is centrally disposed between the ILs 20, 22 and the overlays 40, 42. Thus, the embodiment 207 of Figure 10 shows another exemplary instance of the IL 20, 22 serving an adhesive function between two layers.

[0066] Figure 11 shows a top perspective and exploded view of a multi-layered manufactured wood product 208 with a plurality of ILs 20, 22, 24, 26 under another embodiment. A first IL 20 is shown between a first overlay 40 and a first surface 51 functional filler layer 50; a second IL 22 is shown between the second surface 53 of thefirst functional filler layer 50 and a first side 11 of a strand matrix 10; a third IL 24 is shown between a second side 13 of the strand matrix 10 and a first side 55 of a second functional filler layer 52; and a third IL 26 is shown between the second side 57 of the second functional filler layer 50 and a second overlay 42.

[0067] Figure 12 shows a top perspective and exploded view of a multi-layered manufactured wood product 209 with a plurality of ILs under yet another embodiment. A first IL 20 is shown between a first overlay 40 and a first fines layer 30; a second IL 22 is shown between the first fines layer and a first side 11 of a strand matrix 10; a second fines layer 32 can be seen between the second side 13 of the strand matrix 10 and a third IL 24; and the third IL 24 is shown between the second fines layer 32 and a second overlay 42.

[0068] Figure 13 provides a photographic view of a fines material 30 being deposited on top of an IL 20 during the manufacture of a multi-layered manufactured wood product 300 under one embodiment. As can be seen, the IL 20 can be configured to cover at least one surface of the strand matrix 10, and the IL 20 can comprise a web, a film, a net, or a meshlike structure with a pattern of spaces, pores, or holes therethrough.

[0069] The IL 20 may comprise a fabric (such as, but not limited to, a woven or non-woven synthetic or natural material), specialty papers, resin-saturated papers, pulp mats, glue (adhesive) films, plastic films, minerals, or similar materials that can be used to separate the strand matrix or mat and the fines layer.

[0070] The material can be configured to prevent the passage of at least a portion of the fines material therethrough. In embodiments, the material prevents the majority of the fines material from passing therethrough. In several embodiments, the material is substantially impervious to the fines material. As used herein, the phrase “prevents passage of fines,”“prevent the passage of fines,” and the like can mean that the interface layer blocks at least 50% of fines (as measured by weight) from passing therethrough. In embodiments, the IL blocks at least 75% of fines from passing therethrough. The IL can prevent at least 90% by weight of fines from passing therethrough. In one embodiment, the IL prevents at least 95% of fines from passing therethrough. The IL can prevent the passage of about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98% of fines from passing therethrough.

[0071] In one embodiment, the IL comprises a netted or webbed material. The netted or webbed material can be a textile that is characterized by an open, mesh-like structure. In embodiments, the mesh-like structure is created by interlocking fibers or threads resulting in a pattern of spaces, gaps, pores, or holes. This design allows the material to be breathable, flexible, and lightweight, resembling a net or web. In embodiments, the interlocking fibers or threads are non-woven. The arrangement of threads can vary depending on the intended use. In one embodiment, the threads are arranged to form gaps or “pores” between fibers that form the “web” or “net.” In embodiments, the gaps or “pores” are visible to the naked eye.

[0072] In embodiments, the IL comprises a non-woven web adhesive. In one specific embodiment, the IL comprises a polyamide web adhesive with a latent adhesive property that is activated by heat or steam. In one, non-limiting, exemplary embodiment, the IL comprises Bostik® PAI 15 polyamide web adhesive (available from Bostik SA, Colombes, France) or any other polyamide web with a comparable latent adhesive property.In various exemplary embodiments, the IL comprises a web or net with an average pore size of less than 2.0 mm. In embodiments, the average pore size can be up to 1.0 mm. In certain embodiments, the average pore size is below about 0.5 mm. The average pore size can be less than about 0.4 mm, less than about 0.3 mm, less than about 0.2 mm, or less than about 0.1 mm. The average pore size can be between about 0.05 mm and 0.1 mm. In certain embodiments, the average pore size is as low as about 0.01 mm. The average pore size can be as low as about 0.001 mm. In various embodiments, the average pore size is smaller than the average diameter of the fines within the fines layer. In embodiments, the largest pore size is smaller than the smallest diameter of the fines within the fines layer.

[0073] The material used for the IL cam be compatible with a given manufacturing process, i.e., compatible with any adhesive, additives, heat and / or pressure that may be used. In some embodiments, for example, the manufacturing process comprises high temperatures and pressure.

[0074] In several embodiments, the material of the IL is heat resistant. The material used in the IL can withstand high temperatures or at least 230 degrees F.

[0075] While in some embodiments the IL may be chosen to withstand high temperatures and pressure, in alternative embodiments the IL may be chosen so that the manufacturing process produces changes in the form or configuration of the IL material (e.g., melting or flowing). For example, the IL material may comprise glass or glass-like material, including, but not limited to, binding material that partially or fully melts, flows and / or bonds (adheres) during the pressing process.

[0076] The IL can comprise a material that prevents delamination during use as compared to ILs that comprise impregnated paper or woven or non-woven fabrics, which can beexpensive and may result in poor internal bond and interface adhesion to adjacent layers. In one embodiment, the IL material comprises a solid adhesive that can be applied to at least one layer in a multi-layered panel. Such a solid adhesive IL material can have certain properties that are particularly advantageous in with multi-layered manufactured wood products. For instance, solid ILs can prevent overspray and waste as compared to a fluid-applied IL or a fluid-applied adhesive. Under certain embodiments, the adhesive IL can be used in place of a liquid resin binder to increase interface adhesion of engineered multilayer lignocellulosic composites with less maintenance and storage issues.

[0077] In various embodiments, the IL can comprise a pressure-sensitive adhesive, a heat sensitive adhesive, or a combination thereof. The IL material can comprise a hot-melt adhesive. In embodiments, the IL is in the form of an adhesive sheet or pad. The IL can comprise an adhesive fdm with a mesh-like structure. In one embodiment, the IL is a thermoplastic bonding film. The IL can comprise a thermoplastic adhesive film with a latent adhesive property. The IL can comprise a flame retardant adhesive thermoplastic film. In one embodiment, the interface layer comprises Bostik® FPA110-1FR Flame Retardant Thermoplastic Film Adhesive (available from Bostik SA, Colombes, France) or any other thermoplastic film adhesive with comparable latent adhesive and fire-retardant properties.

[0078] In embodiments, the IL, itself, has an adhesive property. The adhesive property of the IL can be selectively and reversibly activated following application of an activation stimulus such as pressure or heat. Such adhesive property can be latent such that the IL is substantially non-adhesive under standard conditions of use, and the adhesive property isactivated upon application of an external activation stimulus, such as, but not limited to, pressure, heat, or a combination thereof.

[0079] In one embodiment, the IL comprises an adhesive web, an adhesive fdm, an adhesive net, or a combination thereof, wherein the adhesive property is a latent adhesive property. In embodiments, application of the external activation stimulus at an activation threshold causes the IL with a latent adhesive property to transition from a non-adhesive state to an adhesive state, thereby promoting attachment of the IL to an adjacent substrate upon activation. Under one embodiment, the IL is a latent, non-tacky adhesive at room temperature (about 73 °F) that transitions to an adhesive state upon activation (such as application of heat, pressure, or a combination thereof). For instance, in one embodiment, the IL transitions to an adhesive state when the platen temperature reaches or exceeds an activation temperature for at least about 10 seconds. The IL can enter an adhesive state when exposed to the activation temperature (or temperatures greater than the activation temperature) for up to at least about 600 seconds. In embodiments, upon exposure to at least the activation temperature, the IL melts. In embodiments, when placed between at least two layers of a multi-layered panel and exposed to the activation temperature (or any temperature greater than the activation temperature), the IL melts and becomes a fluid that contacts the surfaces of the at least two immediately adjacent layers. Upon cooling to a temperature that is below the activation temperature, the IL can solidify to form an adhesive bond between the at least to layers of the multilayered product. In one embodiment, the IL forms the sole adhesive bond at least two layers of the multi-layered product. The IL can form the sole adhesive between the at least two layers of the multi-layered product without any separately applied adhesive along, within, or upon the interfaces therebetween. Incertain embodiments, no adhesive is applied to material forming the interface layer, fines layer, or strand matrix in regions intended to be bonded by the interface layer. In embodiments bonding between the IL and any immediately adjacent layer is achieved solely following activation of the latent adhesive property of the interface layer alone. The IL can form the sole adhesive layer between any of the one more layers of a multi-layered product without the addition of a glue film, resin, or other adhesive or additive. The IL can form the sole adhesive layer between the fines within the fines layer without the addition of a glue film, resin, or other adhesive or additive. In one non-limiting exemplary embodiment, the IL forms the sole adhesive layer between the fines layer and the strand matrix.

[0080] For heat-activated ILs, activation temperature can range from about 110 °F to about 600 °F. The activation temperature of heat-activated ILs can be greater than 600°F. In embodiments, the activation temperature is at least about 100 °F, at least about 150 °F, at least about 200 °F, at least about 250 °F, at least about 300 °F, at least about 350 °F, at least about 400 °F, at least about 450 °F, at least about 500 °F, at least about 550 °F, or at least about 600 °F. In certain embodiments, activation temperatures of a heat-activated IL is within the range of about 165 °F to about 450 °F. In some embodiments, the activation temperature is at least about 165 °F, at least about 190 °F, at least about 215 °F, at least about 240 °F, at least about 265 °F, at least about 290 °F, at least about 315 °F, at least about 340 °F, at least about 365 °F, at least about 390 °F, at least about 415 °F, or at least about 450 °F.

[0081] In embodiments, the IL can comprise a solvent-cast adhesive that forms a thin, flexible, and versatile layer, which can be heat activated or pressure sensitive forapplications with multiple functions to improve the manufacturing process and properties and performance of multi-layered, engineered bio-composites made from biomass-based elements.

[0082] In embodiments, the IL is substantially free of paper or any other cellulosic sheet material.

[0083] The interface layer can be formed from a single, homogenous substance. In one embodiment, the IL comprises a single, monolithic polymeric layer, such that the IL comprises a single, continuous polymeric phase that is substantially uniform through its thickness. The IL can be formed from a single, homogeneous polymeric material and is substantially free of fibrous sheet substrates. In certain embodiments, the IL comprises a thermoplastic hot-melt polymer. In one non-limiting embodiment, the IL consists essentially of a thermoplastic hot-melt polymer. The IL can comprise any thermoplastic material that is capable of being processed into a sheet or film and melted. Non-limiting, exemplary thermoplastic materials suitable for use within the IL include, but are not limited to polyester, copolyester, polyamide, polyolefin, polypropylene (PP), vinyl acetate (EVA), polystyrene (PS), copolyimide (CO-PA), Teflon™, acrylic, polyurethane (PU), epoxy, silicon, phenolic materials, bio-based resources (e.g., vegetables oils, starches, or other natural polymers), or any combination of the foregoing.

[0084] In certain embodiments, the IL comprises a fire-retardant fillers. In specific embodiments, the IL is a flame retardant, thermoplastic film adhesive.

[0085] The IL disclosed herein can be formulated to improve the heat, moisture, chemical and weathering resistance, impart mold and mildew resistance, improve flatness and dimensional stability of finished products, impart flexibility to laminated panels, or anycombination thereof, particularly following prolonged exposure of a resultant lignocellulosic composite to water vapor during use.

[0086] In various embodiments, the IL can be as thick as about 0.5 inches. In embodiments, the IL is less than about 0.2 inches thick. The IL can comprise a thickness that is less than about 0.1 inches thick. The thickness of the IL can range between about 0.5 mils to about 50 mils. In embodiments, the thickness of the IL is between about 0.5 mils and 7 mils. The IL can have a thickness of about 0.5 mils, about 1.0 mil, about 1.5 mils, about 2.0 mils, about 2.5 mils, about 3.0 mils, about 3.5 mils, about 4.0 mils, about 4.5 mils, about 5.0 mils, about 5.5 mils, about 6.0 mils, about 6.5 mils, about 7.0 mils, about 7.5 mils, about 8.0 mils, about 8.5 mils, about 9.0 mils, or about 10 mils. In embodiments, the IL is less than 1 mil thick. The IL can have a thickness of about 0.9 mils, 0.8 mils, 0.7 mils, 0.6 mils, 0.5 mils, 0.4 mils, 0.3 mils, 0.2 mils, or 0.1 mils. In certain embodiments, the IL is less than about 0.1 mils thick.

[0087] In other embodiments, a stiffening material is added to the IL, so that the IL becomes stiffer and stronger during the pressing process and helps provide additional strength and stiffness to the final product itself. Alternatively, or in addition, the IL may be treated or coated to provide or enhance such properties.

[0088] In further exemplary embodiments, the IL material is selected due to material properties, such as, but not limited to, fire resistance, fungal resistance, moisture / water resistance, sound dampening, or the like. Use of an IL that is fire-resistant can avoid the necessity of pre-treating or pre-coating lignocellulosic materials (such as strand, fines, particles etc.) with fire retardant fillers or additives prior to hot press, which can be timeconsuming and costlier with limited improvement. Moreover, intumescent treatments ascoatings on the outer laminate or overlay can be problematic for long term stability of the bio-composite panel. Thus, use of an IL that comprises fire-retardant properties can simplify the manufacturing process and result in a product with increased stability and use over time.

[0089] The present disclosure further relates methods of improving the manufacturing of multi-layered, engineered bio-composites products. One exemplary method comprises the following steps. Strands / flakes are processed / treated (i.e., cut, dried, and stored 110), then treated and / or coated with adhesive and performance enhancing additives and chemicals (e.g., wax, resin, and the like) 120. Strands designated for particular layers may receive different treatment, although in some cases strands are treated identically regardless of intended layer. The strands are then used to form the appropriate layers in order (e.g., first bottom surface, then core, then top surface), by depositing the designated strands 130, 140, 150 onto the production or forming line to form a multi-layer mat or strand matrix (seen at 10 in Figures 1 and 2). The number of layers can range from 2 to 10 layers (Figure 3 shows 3 layers and Figure 11 shows an embodiment with 9 layers). The number of layers can be greater that 10. In embodiments, the number of layers is between 2 to 20. The interface layer described above is then placed 160 on the upper surface of the mat, followed by application of the fines layer over the IL 170. An overlay (seen at 40 of Figures 1 and 2) or performance overlay (such as, but not limited to, a paper overlay) 180 is then placed on top of the fines layer. The overlay may, for example, comprise a primed paper overlay with performance additives. Overlay materials can be made of various types of products. Exemplary overlay materials include, but are not limited to impregnated kraft paper,saturated papers, low pressure papers, vinyl films, non-wovens, polypropylene sheets, metallic foils, veneers, and the like.

[0090] The assembled, unbonded layers are then subjected to further processing depending on the final product desired. Suitable adhesives include but are not limited to those selected from an isocyanate, phenolic, hot-melt polyurethane or melamine category alone or in combination. However, in embodiments wherein the IL comprise an adhesive film, the use of such additional adhesives may be unnecessary.

[0091] In certain embodiments, pressure may be applied using several methods including but not limited to a hot press, cold press or steam-injection press. The process may be continuous or non-continuous (batch) or a combination or hybridization of these. Heat may be conveyed using various methods, to include but not be limited to steam, microwaves, thermal oil and the like. During hot press, condensation reaction could occur between thermoset type of adhesive web, film, and net and lignocellulose within biomass-based materials. Inter and intra hydrogen bond (H-bond) can be formed during hot press among the polarized functional groups in both biomass-based lignocellulose and IL, e.g., hydroxyl groups, uronic acid, carboxylic acids, amides, and imides, urethane groups, phenolic groups, etc.

[0092] For example, in one embodiment the assembled, unbonded layers are conveyed into a press for final consolidation and bonding under pressure. In another embodiment, as seen in Figure 3, the assembled, unbonded layers are conveyed into a hot press 190 for final consolidation and bonding under heat and pressure. In yet another embodiment, the assembled, unbonded layers are subjected to microwaves with or without a heated platen. In a further embodiment, the assembled, unbonded layers are subjected to super-heatedsteam. After pressing, the resulting board may then be subject to further post-press processing 200 (e.g., additional overlays, secondary pressing or processing, trimming, sizing, priming, sealing, and packaging), depending on the desired final end product.

[0093] The present invention may be used with any engineered wood manufacturing process, regardless of the end-use application, and is not limited to siding. In embodiments, the multi-layered product disclosed herein comprises a building panel. The multi-layered product can comprise wood, plywood, OSB, plastic, metals, wallboard, medium density fiberboard (MDF), particle board, or any combination thereof.

[0094] In certain embodiments, multi-layered product can comprise OSB manufactured as part of a “combination” product, such as, but not limited to, an OSB strand core with particleboard or fiberboard faces. The IL disclosed herein can be employed within any type of panel for interior or exterior use. In embodiments, the IL and associated method can be used in siding, trim, fencing wall sheathing, roof sheathing, other sheathing, indoor decorative panels, or any combination thereof. Non-limiting, exemplary multi-layered products can take the form of a planar sheet, such as a 4-foot by 8-foot panel, but smaller and / or larger substrates are also equally possible.

[0095] Similarly, ILs may be used on one or both faces or surfaces of a product (i .e., a two-surface smooth product). If a single IL is used, it may be used on the bottom surface or top surface of the product. Alternatively, the IL may be disposed upon or between any layer between the top surface and the bottom surface. Thus, the IL may be used on the top surface only, the bottom surface only, on both the top and bottom surfaces, or on any layer therebetween. In the case of an IL used on the bottom surface, the above-described method is modified to include a step of placing a bottom IL on the forming or production line priorto the formation of the bottom layer of the mat 10 (the bottom layer of the mat is then formed on the bottom IL).

[0096] 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.

Claims

CLAIMSWhat is claimed is:

1. An improved method of producing a multi-layered engineered wood product, comprising the steps of:forming at least one layer of the multi-layered engineered wood product, said at least one layer comprising a top surface;applying an interface layer with a latent adhesive property on the top surface of the at least one layer of the multi-layered engineered wood product, wherein:the interface layer comprises a web, a film, a net, or a combination thereof; the interface layer comprises an upper surface opposite the layer to which the interface layer is applied; andconsolidating and bonding the interface layer and the at least one layer together using heat, pressure, or a combination thereof to form a multi-layered engineered wood product.

2. The method of claim 1, further comprising forming a fines layer on the upper surface of the interface layer, whereinthe fines layer comprises a plurality of fines; andthe interface layer is configured to prevent the passage of at least a portion of the fines from the fines layer into the at least one layer.

3. The method of claim 2, wherein the at least one layer comprises a strand matrix, and the interface layer is configured to prevent the passage of the majority of fines from the fines layer into the strand matrix.

4. The method of claim 1, wherein the interface layer comprises a flexible material.

5. The method of claim 1, wherein the interface layer is a thermoplastic, thermoset, or pressure-sensitive material.

6. The method of claim 4, wherein the flexible material is a synthetic or natural material.

7. The method of claim 1, wherein the interface layer comprises polyester, polyamide, polyolefin, polypropylene, vinyl acetate, polystyrene, copolyimide, polytetrafluoroethylene, acrylic, polyurethane, epoxy, silicone, or any combination thereof.

8. The method of claim 1, wherein the interface layer comprises phenolic-based material.

9. The method of claim 8, wherein the interface layer comprises a vegetable oil, a starch, another natural polymer, or any combination thereof.

10. The method of claim 1, wherein the interface layer partially or fully melts upon reaching an activation temperature during the step of consolidating and bonding.

11. The method of claim 1 , wherein the interface layer comprises a material with a melting point between about 165 °F to about 450 °F.

12. The method of claim 1, wherein the interface layer provides one or more of the following: fire resistance; fungal resistance; moisture resistance; and sound dampening.

13. The method of claim 2, further comprising the step of applying an overlay on an upper surface of the fines layer opposite the interface layer.

14. The method of claim 1, wherein the step of consolidating and bonding comprises application of heat and pressure using a hot press.

15. The method of claim 1, wherein the step of consolidating and bonding comprises application of pressure using a cold press.

16. The method of claim 1, wherein the step of consolidating and bonding comprises application of microwaves with or without a heated platen.

17. The method of claim 1, wherein the step of consolidating and bonding comprises application of super-heated steam.

18. An engineered-wood product produced by the method of claim 1.

19. The product of claim 18, wherein the engineered-wood product is an Oriented-Strand Board (OSB) plank, board or panel.

20. The product of claim 18, wherein the engineered-wood product is a siding, cladding or panel.

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