Title:
Wood panel
Kind Code:
A1


Abstract:
A wood panel is provided comprising: a composite wood component having upper and lower surface layers and a core layer; and a veneer component, having a thickness of about 1/64″ to about ¼″, attached to the upper surface layer of the wood composite.



Inventors:
Cecilio, Federico R. (Athens, GA, US)
Gerello, Brian C. (Statham, GA, US)
Application Number:
10/903022
Publication Date:
02/16/2006
Filing Date:
07/30/2004
Primary Class:
International Classes:
E04F13/08
View Patent Images:
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Primary Examiner:
THOMAS, ALEXANDER S
Attorney, Agent or Firm:
David M. Goodrich;J. M. Huber Corporation (333 Thornall St., Edison, NJ, 08837, US)
Claims:
We claim:

1. A wood panel comprising: a composite wood component having upper and lower surface layers and a core layer; and a veneer component, having a thickness of about 1/64″ to about ¼″, attached to the upper surface layer of the wood composite.

2. The wood panel according to claim 1, comprising a second veneer component attached to the lower surface layer of the composite wood component.

3. The wood panel according to claim 1, wherein the composite wood component is oriented strand board.

4. The wood panel according to claim 2, wherein an exterior face of the upper surface layer and an exterior face of the lower surface layer have been sanded.

5. The wood panel according to claim 4, wherein a resin is applied to the exterior face of the upper surface layer and the exterior face of the lower surface layer.

6. The wood panel according to claim 5, wherein the resin is applied at a concentration of about 6 g/ft2 to about 20 g/ft2.

7. The wood panel according to claim 1, wherein the veneer is selected from the group comprising red oak, white oak, birch, maple, cherry, walnut, poplar, sweet gum, sycamore, tupelo, white gum, Carolina pine, ponderosa pine, lodgepole pine, Douglas fir, white fir, spruce, hemlock, rosewood, teak and mahogany.

8. The wood panel according to claim 1, wherein the veneer component is laminated to the upper surface layer of the composite wood component.

9. The composite material piece of claim 1, wherein the upper and lower surface layers are each comprised of wood strands substantially oriented in a first direction, wherein the wood strands are bonded by curing of a binder material contacting the wood strands where the binder material is substantially free of water and comprised of a curable powdery aldehyde resin and a curable isocyanate resin; and a core layer located between and bonded to the first and second surface layers, where the core layer comprises wood strands substantially oriented in a second direction that is different from the first direction.

10. A process for preparing a wood panel comprising the steps of: providing a composite wood component, the wood component including an upper surface layer, the upper surface layer having an exterior face; providing a veneer component, having a thickness of about 1/64″ to about ¼″; sanding the exterior face of the upper surface layer; applying an adhesive resin to the exterior face of the upper surface layer to form a resin applied exterior face; and contacting the veneer component to the resin applied exterior face to form a wood panel.

11. The process for preparing a wood panel according to claim 10, wherein the veneer component is contacted to the resin applied exterior face at a pressure of about 75 psi to about 200 psi.

12. The process for preparing a wood panel according to claim 10, wherein the resin is applied at a concentration of about 6 g/ft2 to about 20 g/ft2.

13. The process for preparing a wood panel according to claim 10 wherein the veneer is selected from the group comprising red oak, white oak, birch, maple, cherry, walnut, poplar, sweet gum, sycamore, tupelo, white gum, Carolina pine, ponderosa pine, lodgepole pine, Douglas fir, white fir, spruce, hemlock, rosewood, teak and mahogany.

14. The process for preparing a wood panel according to claim 10, wherein the veneer component is contacted to the resin applied exterior face at a temperature of about 150° F. to about 300° F.

15. The process for preparing a wood panel according to claim 10, wherein the composite wood component is oriented strand board.

16. The process for preparing a wood panel according to claim 10, wherein the contacting steps lasts between about 1 minute to about 10 minutes.

17. The wood panel according to claim 1, wherein the veneer component is coated with a protective, polymeric coating, the coating cured by a technique selected from the group comprising UV-curing, RF curing, E-band curing, and air drying.

18. An article of furniture comprising the wood panel according to claim 1.

19. The wood panel according to claim 1, wherein the RMSsmoothness has a value of less than 25 micrometers.

20. A wood panel comprising: a composite wood component having upper and lower surface layers containing wood strands substantially oriented in a first direction, wherein the wood strands are bonded by curing of a binder material contacting the wood strands where the binder material is substantially free of water and comprised of a curable powdery aldehyde resin and a curable isocyanate resin; and a core layer located between and bonded to the first and second surface layers, where the core layer comprises wood strands substantially oriented in a second direction that is different from the first direction; a veneer component attached to the upper surface layer of the wood composite core; and a resin applied to the exterior face of the upper surface layer and the exterior face of the lower surface layer at a concentration of about 6 g/ft2 to about 20 g/ft2.

Description:

BACKGROUND OF THE INVENTION

Wood can be used to construct almost any part of a home from the roofing and exterior walls to the floor and interior architectural elements as well as basic domestic items like furniture and cabinets. However, in recent years the cost of solid timber wood has increased dramatically as its supply shrinks due to the gradual depletion of old-growth and virgin forests. Indeed, it is particularly expensive to manufacture solid hardwood furniture and architectural features from such material because typically less than half of harvested timber wood is converted to natural solid wood lumber, the remainder being discarded as scrap.

Accordingly, because of both the cost of high-grade timber wood as well as a heightened emphasis on conserving natural resources, wood-based alternatives to natural solid wood lumber have been developed that make more efficient use of harvested wood and reduce the amount of wood discarded as scrap. Plywood, particle board and oriented strand board (“OSB”) are examples of wood-based composite alternatives to natural solid wood lumber that have replaced natural solid wood lumber in many structural applications in the last seventy-five years. These wood-based composites not only use the available supply of timber wood more efficiently, but they can also be formed from lower-grade wood species, and even from wood wastes.

These wood-based composite materials do offer a highly efficient way to use available wood material, however, because they typically consist of small particles (particle board), wood strands (OSB), flat pieces of low-grade wood species or some similar such material, products made from them do not have an attractive, grained appearance, but rather tend to have unsatisfactory aesthetic finishes. This may make them unsuitable for use in interior furnishings and for articles of furniture and cabinetry.

One approach to addressing this aesthetic drawback is to prepare a special wood composite material by placing decorative veneer layers having a wood or wood grain appearance upon the top and bottom surfaces of an internal, or “core” composite wood material. These veneer sheets are very thin, having a thickness of no greater than ⅛ inch, and are typically made from a decorative wood material, such as oak.

However, while these veneer-covered wood composite materials do have improved aesthetic finishes, they can be somewhat difficult to prepare and manufacture. In particular is a common problem referred to as “telegraphing”, where due to the thinness of the veneer layer, the texture of the underlying wood composite material presses through the veneer layer creating a non-uniform, uneven surface with numerous imperfections.

Several solutions have been proposed to eliminate surface telegraphing. One technique is to use an intermediate layer between the core layer (especially an oriented strand board core layer) and the veneers such as is described in U.S. Pat. No. 5,506,026. This intermediate layer provides a smooth surface onto which the veneers may be laminated. While this technique is often effective it also creates a five-ply product that is considerably more expensive because of additional labor and material costs than a three-ply product. Other investigators, such as shown in U.S. Pat. No. 6,461,743 have considered using a combination of both an intermediate layer and additional control over the surface. But while this does adequately ameliorate surface telegraphing, it is even more time-intensive and costly than merely using an intermediate layer without further pretreatment.

Still another technique for preventing surface telegraphing is the application of a coating or putty to hide the texture or surface imperfections on the wood composite's surface, such as shown in U.S. Pat. No. 5,616,419. Unfortunately, this technique not only often fails to prevent telegraphing, it is also time consuming to distribute the glue across the surface of the wood composite material in sufficient concentration and evenness to ensure that the surface telegraphing will be absent.

Given the foregoing, there is a continuing need for an efficiently constructed wood composite material that has the excellent surface finish to be useful for applications where surface appearance is important such as interior domestic furnishings, furniture and cabinetry.

BRIEF SUMMARY OF THE INVENTION

The present invention includes a wood panel comprising: a composite wood component having upper and lower surface layers and a core layer; and a veneer component, having a thickness of about 1/64″ inch to about ¼″, attached to the upper surface layer of the wood composite.

The present invention also includes a process for preparing a wood panel comprising the steps of: providing a composite wood component, the wood component including an upper surface layer, the upper surface layer having an exterior face; providing a veneer component, having a thickness of about 1/64″ inch to about ¼″; sanding the exterior face of the upper surface layer; applying an adhesive resin to the exterior face of the upper surface layer to form a resin applied exterior face; and contacting the veneer component to the resin applied exterior face to form a wood panel.

DETAILED DESCRIPTION OF THE INVENTION

All parts, percentages and ratios used herein are expressed by weight unless otherwise specified. All documents cited herein are incorporated by reference.

As used herein, “wood” is intended to mean a cellular structure, having cell walls composed of cellulose and hemicellulose fibers bonded together by lignin polymer.

By “laminated”, it is meant material composed of layers and bonded together using resin binders.

By “wood composite material” or “wood composite component” it is meant a composite material that comprises wood and one or more other additives, such as adhesives or waxes. Non-limiting examples of wood composite materials include oriented strand board (“OSB”), structural composite lumber (“SCL”), waferboard, particle board, chipboard, medium-density fiberboard, plywood, and boards that are a composite of strands and ply veneers. As used herein, “flakes”, “strands”, and “wafers” are considered equivalent to one another and are used interchangeably. A non-exclusive description of wood composite materials may be found in the Supplement Volume to the Kirk-Othmer Encyclopedia of Chemical Technology, pp 765-810, 6th Edition, which is hereby incorporated by reference.

The following describes preferred embodiments of the present invention, which provides a wood panel comprising a wood composite component and a veneer component. Because the composite material piece does not display surface telegraphing through the veneer component, it is particularly useful for constructing furniture and cabinetry where a wood-grain appearance is important but where the use of solid timber wood would be prohibitively expensive. While not intended to be limited by theory, it is believed that in the present invention surface telegraphing has been avoided by a combination of two important processing steps: first, a consistent application of fine grit sandpaper through the sander to minimize thickness variation of the composite wood material and maximize pre-lamination smoothness; and second a thorough cleaning after sanding of left-over dust, other process particulates and release agent that may affect bond formation between the composite wood material and the veneers. The inventors have taken an extra step of using air blowers in addition to the installed sander equipment. The wood panel prepared according to the present invention is particularly useful for hardwood floors, and articles of furniture such as tables, table tops, book cases, and cabinetry. After being prepared in the method described above, the wood panel will be so smooth as to have an RMSsmoothness (as defined below) of less than 25 micrometers.

Wood Veneer Component

The wood veneer component may be selected from a variety of natural materials such as red oak, white oak, birch, maple, cherry, walnut, poplar, sweet gum, sycamore, tupelo, white gum, Carolina pine, ponderosa pine, lodgepole pine, Douglas fir, white fir, spruce, hemlock, rosewood, teak and mahogany. The veneers may be produced by standard veneer production techniques such as rotary slicing, rift-cut, quarter slicing, half-round slicing, plain slicing, and lengthwise slicing. Preferably, the thickness of the veneer slice is between about 1/64″ inch to about ¼″, more preferably between 1/42″ inch and 1/16″ inch. Suitable veneer materials are available from Clarke Veneers, Jackson Miss., as well as other distributors in North America through the HPVA (Hardwood Plywood and Veneer Association), Reston, Va. The thinness of the veneer varies somewhat with the material from which the veneer is constructed. For a material such as oak, the veneer must be at least 1/64″, while for cherry the veneer could be as thin as 1/128″. The veneer must be sufficiently thick that it can be sanded without damaging it, and also sufficiently thick that it is not necessary to attach a paper or other supporting backer to it to give it structural integrity.

The veneer component may be treated with a protective, polymeric coating, with the coating cured by a technique selected from the group comprising UV-curing, RF curing, and E-band curing. The material may also be allowed to air dry. Suitable coatings include the UVN-700 coatings available from Valspar Corp., and the ZVOC Product line available from UV Corporation.

Wood Composite Component

Preferably, the wood composite component is made from OSB material. The oriented strand board is derived from a starting material that is naturally occurring hard or soft woods, singularly or mixed, whether such wood is dry (having a moisture content of between 2 wt % and 12 wt %) or green (having a moisture content of between 30 wt % and 200 wt %). Typically, the raw wood starting materials, either virgin or reclaimed, are cut into strands, wafers or flakes of desired size and shape, which are well known to one of ordinary skill in the art.

After the strands are cut they are dried in an oven and then coated with a special formulation of one or more polymeric thermosetting binder resins, waxes and other additives. The binder resin and the other various additives that are applied to the wood materials are referred to herein as a coating, even though the binder and additives may be in the form of small particles, such as atomized particles or solid particles, which do not form a continuous coating upon the wood material. Conventionally, the binder, wax and any other additives are applied to the wood materials by one or more spraying, blending or mixing techniques, a preferred technique is to spray the wax, resin and other additives upon the wood strands as the strands are tumbled in a drum blender.

After being coated and treated with the desired coating and treatment chemicals, these coated strands are used to form a multi-layered mat, preferably a three layered mat. This layering may be done in the following fashion. The coated flakes are spread on a conveyor belt to provide a first ply or layer having flakes oriented substantially in line, or parallel, to the conveyor belt, then a second ply is deposited on the first ply, with the flakes of the second ply oriented substantially perpendicular to the conveyor belt. Finally, a third ply having flakes oriented substantially in line with the conveyor belt, similar to the first ply, is deposited on the second ply such that plies built-up in this manner have flakes oriented generally perpendicular to a neighboring ply. Alternatively, but less preferably, all plies can have strands oriented in random directions. The multiple plies or layers can be deposited using generally known multi-pass techniques and strand orienter equipment. In the case of a three ply or three layered mat, the first and third plys are surface layers, while the second ply is a core layer. The surface layers each have an exterior face.

The above example may also be done in different relative directions, so that the first ply has flakes oriented substantially perpendicular to conveyor belt, then a second ply is deposited on the first ply, with the flakes of the second ply oriented substantially parallel to the conveyor belt. Finally, a third ply having flakes oriented substantially perpendicular with the conveyor belt, similar to the first ply, is deposited on the second ply.

Various polymeric resins, preferably thermosetting resins, may be employed as binders for the wood flakes or strands. Suitable polymeric binders include isocyanate resin, urea-formaldehyde, polyvinyl acetate (“PVA”), phenol formaldehyde, melamine formaldehyde, melamine urea formaldehyde (“MUF”) and the co-polymers thereof. Isocyanates are the preferred binders, and preferably the isocyanates are selected from the diphenylmethane-p,p′-diisocyanate group of polymers, which have NCO-functional groups that can react with other organic groups to form polymer groups such as polyurea, —NCON—, and polyurethane, —NCOON—; a binder with about 50 wt % 4,4-diphenyl-methane diisocyanate (“MDI”) or in a mixture with other isocyanate oligomers (“pMDI”) is preferred. A suitable commercial pMDI product is Rubinate 1840 available from Huntsman, Salt Lake City, Utah, and Mondur 541 available from Bayer Corporation, North America, of Pittsburgh, Pa. Suitable commercial MUF binders are the LS 2358 and LS 2250 products from the Dynea corporation.

The binder concentration is preferably in the range of about 3 wt % to about 8 wt %. A wax additive is commonly employed to enhance the resistance of the OSB panels to moisture penetration. Preferred waxes are slack wax or an emulsion wax. The wax solids loading level is preferably in the range of about 0.1 wt % to about 3.0 wt % (based on the weight of the wood).

It is preferable that the surface layers in the present invention make use of the following enhanced resin composition. This resin composition involves the simultaneous application of an isocyanate resin and a powdered aromatic phenol-aldehyde thermoset material in the same blender in the preparation of the surface layers of the OSB. The powdered aromatic aldehyde thermoset effectively replaces a fraction of the MDI resin that otherwise would be needed. Preferably, a powdered phenol-formaldehyde is used that penetrates very well inside curled flakes of the surface layer(s) of the OSB. It also enhances resin distribution inside the curled flakes in the surface layer of OSB to improve the board product quality by reducing curled flake failures without increasing resin costs. The MDI binder ingredient renders the OSB structurally strong and durable and generally improves the water resistance, while the phenol-formaldehyde ingredient prevents flake popping and improves strength of the OSB among other things. The resin binder system used for one or both the OSB surface layers, as initially reacted, preferably is non-aqueous and contains no water or, at most, only nominal impurity levels (viz., less than 1 wt. % and preferably less than 0.5 wt. % water based on the total weight of the binder system). This resin composition and its methods for use are described in greater detail in U.S. Pat. No. 6,479,127.

After the multi-layered mats are formed according to the process discussed above, they are compressed under a hot press machine that fuses and binds together the wood materials, binder, and other additives to form consolidated OSB panels of various thickness and sizes. The high temperature also acts to cure the binder material. Preferably, the panels of the invention are pressed for 2-15 minutes at a temperature of about 175° C. to about 240° C. The resulting composite panels will have a density in the range of about 35 lbs/ft3 to about 48 lbs/ft3 (as measured by ASTM standard D1037-98). The density ranges from 40 lbs/ft3 to 48 lbs/ft3 for southern pine, and 35 lbs lbs/ft3 to 42 lbs/ft3 for Aspen. The thickness of the OSB panels will be from about 0.6 cm (about ¼″) to about 5 cm (about 2″), such as about 1.25 cm to about 6 cm, such as about 2.8 cm to about 3.8 cm.

An important part of the present invention is that the exterior faces of the upper and lower surfaces are thoroughly sanded before the veneer components are attached to the upper and lower surfaces. Preferably this is done with a 120 grit or 60 grit sand paper. A minimum of 1/64″ should be sanded from each side for a minimum total of 1/32″. Suitable sanders are available from Timesavers, Inc., Minneapolis, Minn.

After the sanding is completing the sanded surface are thoroughly cleaned to remove left-over dust, process particulates and release agents that may affect bond formation between the wood composite material and the veneers. Particularly important is the use of blowers to remove the dust and particulates from the surface of the board, such blowers can be built into the sanding equipment.

Alternatively, other equipment that can be used for removing particulates includes an air knife or brush, which applies a uniform flow of air across the surface of the board to remove particles or debris. Suitable air knives include the “Standard Air Knife™”, and the “Super Air Knife™” from the Exair Corporation, Cincinnati, Ohio. Air may be supplied either to the blowers mounted on the sanding equipment or to the air knife or air brush from an air compressor. Other methods for removing particulates, such as vacuums, are also acceptable.

Next, the engineered wood component (e.g., the OSB panel prepared according to the aforementioned procedure) and the veneer component are attached to each other to form a composite piece. Such attachment occurs such as by adhesively bonding the veneer component to the exterior faces of the surface layers, such as by lamination. Common wood adhesives, such as polyvinyl acetate, urea formaldehyde, MDI are applied to each of the components and the components brought into contact with each other to form an adhesive bond. The adhesives are applied at a concentration of about 6 g/ft2 to about 20 g/ft2, preferably about 10 g/ft2 to about 15 g/ft2. The components are brought into contact with each other using a typical 4′×8′ hot-press and held together for a period of about 1 minute to about 10 minutes, preferably about 2 minutes to about 5 minutes to establish a good adhesive bond. The press pressure was maintained of about 75 psi to about 200 psi, preferably about 120 psi to about 150 psi, and the press temperature was held at about 150° F. to about 300° F., preferably about 175° F. to about 225° F.

The orientation of the attached wood veneer component relative to the wood composite component is important. The veneer component may be attached so that the grain direction of the veneer component is substantially parallel or substantially perpendicular to the strands on the exterior faces of the wood composite component. The preference for the orientation of the grain direction of veneer with respect to the strands in the surface layer of the OSB is determined by its end use. While it is preferred that the strands be oriented within a layer to provide stiffness and strength, it is understood by those skilled in the art that the strands can also be random, and the veneer grain direction would be oriented in a desirable direction with respect to the dimensions of the panel.

The invention will now be described in more detail with respect to the following, specific, non-limiting examples.

EXAMPLES

Several wood panels were made according to the present invention. All of these examples were made starting with an Advantech® OSB, available from Huber Engineered Woods, Charlotte, N.C. The particular Advantech® OSB used was produced at Huber mills in White's Creek, Tenn. and Commerce, Ga. The Advantech® OSB was in the form of panels having dimensions of 23/32 inch×4 feet×8 feet, but before testing the panels were cut down to a 4 feet by 4 feet size. Before having the veneer applied, the panels were sanded using a sander having either 120 grit or 60 grit sand paper to a thickness of 11/16 inch. The particulate matter was cleared off the board using blowers attached to the sanders and then further cleared with an airwand with 75 psi pressure. The Veneers used selected were from Clarke Veneers and included red oak P/S Grade A ( 1/42 inch thickness), natural birch rotary #1 ( 1/36 inch thickness), red oak rotary #1 ( 1/36 inch thickness), natural birch P/S grade A ( 1/42 inch thickness).

The process parameters for adhesively bonding the veneer to the OSB were as follows:

    • Press pressure: 150 PSI.
    • Press Temperature: 200° F.
    • Press Time: 3 minutes
    • Adhesive Concentration: 10 grams/ft2

The surface profile of the panels was measured to determine smoothness and thus the degree to which the underlying OSB material “telegraphed” through the veneer. The smoother the surface profile, the less telegraphing and thus, the better board performance. The surface profile was measured using a wood surface profiler.

The surface profile was measured by the following procedure. A Mitutoyo SJ-201P (with a 0.75 inch sized detector) was used to make several measurements, in which a first measurement was made, and defined as the “datum” for that panel, and then several subsequent measurements made, and compared to the datum, with a positive measurement indicating a peak, and a negative measurement indicating a valley. Thus, the measurement system is capable of distinguishing not only the magnitude of the deviations, but also the direction of the differences themselves. (This processed is then repeated thrice for each board).

From this data a smoothness value having units of micrometers, RMSsmoothness, was calculated according to the following formula: RMSsmoothness=(1N1NYi2)
Where:

    • N=is the number of test measurements per panel, with each panel representing an independent set of experimental conditions;
    • Yi=are the individual vertical distance measurements from the horizontal datum initially set by the profiler, measured in micrometers.

As described above, after manufacture the surface profile was measured to obtain the RMSsmoothness. The panels were then tested to determine their performance under high moisture conditions. This moisture condition testing was conducted by exposing them to the following schedule of temperature and humitidity conditions:

    • 5 days at 90° F., 90% relative humidity; and then
    • 5 days at 30° F., 20% relative humidity.

After these 10 days of moisture conditioning testing, the surface profile was again measured to determine the “conditioned” RMSsmoothness.

Along with the several aforementioned wood panels that were made according to the present invention, the surface profile of several additional panels representing prior art, industry standard veneer-covered wood composite materials were also measured in order to determine the RMSsmoothness. The results for the wood panels made according to the present invention, and the prior art wood panels were as follows.

TABLE I
Wood Panels Prepared According to the present invention
Veneer?RMSsmoothness (μm)
SandingThicknesscondi-vari-
Gritmaterial(inch)adhesivedrytionedation
120Birch1/36PVA22.4124.582.17
120Oak1/36PVA10.9411.920.98
60Birch1/36PVA12.0222.4610.44
60Oak1/36PVA10.5712.672.10
120Birch1/42PVA23.3126.373.06
120Oak1/42PVA13.1815.502.32
60Birch1/42PVA18.9330.0811.15
60Oak1/42PVA16.9324.157.22
120Birch1/36UF22.6030.628.02
120Oak1/36UF10.7413.432.69
60Birch1/36UF14.7625.3910.63
60Oak1/36UF12.2619.637.37
120Birch1/42UF12.5516.523.97
120Oak1/42UF17.9818.950.97
60Birch1/42UF12.6416.393.75
60Oak1/42UF12.2717.965.69

The composite wood component for the samples in Table I was Advantech® OSB made in Commerce, Ga. The PVA was obtained from Ashland Chemicals, specification CM 408, while the UF was obtained from Dynea Resin, specification Prefere 4213. The veneers used were 1/42 inch red oak P/S grade A, 1/36 inch red oak rotary #1, 1/42″ natural birch P/S grade A, and 1/36 inch natural birch rotary #1. All the veneers used were from Clarke Veneers.

TABLE II
Wood Panels Prepared According to the present invention
Veneer?RMSsmoothness (μm)
SandingThicknesscondi-
Gritmaterial(inch)adhesivedrytionedvariation
120Birch1/36PVA19.2426.877.63
120Oak1/36PVA11.4711.920.45
60Birch1/36PVA25.5632.446.88
60Oak1/36PVA11.0111.400.39
120Birch1/42PVA19.0020.061.06
120Oak1/42PVA11.0014.803.80
60Birch1/42PVA14.0118.164.15
60Oak1/42PVA13.2219.095.87
120Birch1/36UF19.5820.791.21
120Oak1/36UF11.5817.325.74
60Birch1/36UF19.1725.396.22
60Oak1/36UF11.9414.082.14
120Birch1/42UF15.0321.566.53
120Oak1/42UF12.8514.631.78
60Birch1/42UF11.8812.760.88
60Oak1/42UF21.0027.146.14

The composite wood component for the samples in Table II was Advantech® OSB made in White's Creek, Tenn. The PVA was obtained from Ashland Chemicals, specification CM 408, while the UF was obtained from Dynea Resin, specification Prefere 4213. The veneers used were 1/42 inch red oak P/S grade A, 1/36 inch red oak rotary #1, 1/42″ natural birch P/S grade A, and 1/36 inch natural birch rotary #1. All the veneers used were from Clarke Veneers.

TABLE III
Industry Standard Materials
RMSsmoothness
Industry Standard MaterialDryConditionedVariation
OAK
Particle Board with7.9512.164.21
Oak veneer
MDF with17.4118.881.47
Oak veneer
Plywood with27.7228.911.19
Oak veneer
BIRCH
Particle Board with11.9715.984.01
Birch veneer
MDF with12.2117.565.35
Birch veneer
Plywood with8.0615.587.52
Birch veneer

Surprisingly and unexpectedly, visual telegraphing did not occur in some of the conditions. As can be seen by comparing Tables I-III, the wood panels prepared according to the present invention performed very well compared to the industry standard materials. For example, the panels made according to the present invention with oak veneers and PVA adhesive had lower measured RMSsmoothness values after being exposed to the humidity conditioning test than all of the industry standard materials. Thus, the panels made according to the present invention with oak veneers and PVA performed better than the prior art industry standard materials.

Similarly, the panels made according to the present invention with oak veneers and UF adhesive also did very well, as can be seen by comparing their RMSsmoothness values to those of the industry standard materials. Only the particle board with oak veneer industry standard material performed better than the panels of the present invention having oak veneers after the humidity conditioning test.

Panels made according to the present invention with birch veneers also performed very well: consistently offering comparable performance to the prior art industry standard materials with birch veneer. However, in contrast to the prior art industry standard materials, the panels of the present invention can be easily made without time consuming and extra processing steps like the addition of extra material layers or the application of a resin or coating on top of the composite wood material, as is necessary in the prior art.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.