Note: Descriptions are shown in the official language in which they were submitted.
CA 02604613 2007-10-23
-1-
COMPOSITE BUILDING
COMPONENTS AND METHOD OF MAKING SAME
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates generally to man-made composite building components and
their method of manufacture and assembly. More particularly, the invention
relates to the
production of composite framing members and integrated components such as
studs,
walls, roofs, floors, and posts.
Description of Related Technology
In conventional building construction, building components such as walls,
roofs,
floors, and posts may be assembled from wooden framing members and sheathing.
Framing members, e. g., lumber, may be produced from natural wood cut in
standard
sizes from trees such as aspen, spruce, pine, and fir. Sheathing, typically
made of
plywood or oriented strandboard (OSB), is fastened to the frame of a building
component
using mechanical fasteners and adhesives such as staples, nails, glue, screws
or a urethane
foam adhesive.
CA 02604613 2007-10-23
at ~
WO 01/75245 PCTIUSOO/27575
-2-
Traditional lumber produced from natural wood generally has
shortcomings in consistency, availability, and cost. Likewise, building
components made from traditional materials also have shortcomings in
consistency, cost, and ease of assembly.
Conventional lumber from natural wood varies widely in
quality. Because framing members, such as nominal 2x4s (actually
measuring approximately 11/2 inches by approximately 31/2 inches), are cut
whole from trees or logs as solid pieces, they can possess faults inherent in
natural wood, such as knots and splits. Knots typically result in reduced
strength in a piece of lumber, requiring a high design safety factor leading
to
inefficient use of materials. In addition, in a condition known as "waning,"
lumber cut from an outer surface of a tree, particularly from younger,
smaller trees, can exhibit an undesirable rounded, rather than squared; edge.
Also, subsequent to milling, lumber can take on moisture or dry out, which
causes a board to become warped and unusable for its intended purpose.
These faults contribute to 30-35 % of conventional lumber being of a
downgraded quality rating.
The lumber that remains suitable for use in construction must
often be trimmed, shimmed, nailed to fit, or otherwise adapted for use due to
inconsistencies in dimensional accuracy. Furthermore, once installed,
lumber is subject to dimensional instability due to environmental factors or
the other factors mentioned above. For example, in a condition known as
nail pop, installed lumber dries out and shrinks, causing fasteners to move or
break loose. Likewise, accidental contact with water or moisture can cause
wood to swell and permanently warp.
Natural wood used to produce lumber also is becoming more
and more scarce, especially in larger sizes, due to the depletion of old
growth forests. This scarcity naturally leads to reduction in quality and/or
to
CA 02604613 2007-10-23
-3-
the rising cost of conventional lumber and of the homes and businesses built
with lumber.
This application also relates to cellulosic, composite articles. One type of
composite article is a wood composite such as a man-made board of bonded wood
elements and/or lignocellulosic materials, commonly referred to in the art by
the
following exemplary terms: fiberboards such as hardboard, medium density
fiberboard,
and softboard ; chipboards such as particleboard, waferboard, strandboard,
OSB, and
plywood. Wood composites also include man-made boards comprising combinations
of
these materials.
Many different methods of manufacturing OSB are known in the art, such
as, for example, those described in Chapter 4.3 of the Wood Reference
Handbook,
published by the Canadian Wood Council, and The Complete Manual of
Woodworking,
by Albert Jackson, David Day and Simon Jennings.
The first step in producing a wood composite is to obtain and sort the logs,
which may be aspen, balsam fir, beech, birch, cedar, elm, locust, maple, oak,
pine, poplar,
spruce, or combinations thereof. The logs may be soaked in hot water ponds to
soften the
wood for debarking. Once debarked, the logs are then machined into strands by
mechanical cutting means. The strands thus produced are stored in wet bins
prior to
drying. Once dried to a consistent moisture content, the strands are generally
screened to
reduce the amount of fine particles present. The strands, sometimes referred
to as the
filler material, are then mixed in a blending operation, adding a resin
binder, wax, and
any desired performance- enhancing additives to form the composite raw
material,
sometimes called the furnish. The resin-coated or resin-sprayed strands then
are deposited
onto a forming line, which arranges the strands to form a loosely felted mat.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-4-
The mat thus formed also can be referred to as an array of strands. The mat,
including one or more layers of strands arranged with a selected orientation
(including, for example, a random orientation), is then conveyed into a
press. The press consolidates the mat under heat and pressure, polymerizing
the resin and binding the strands together to form a consolidated array of
strands with other additives, including the binder. The boards are then
conveyed out of press into sawing operations which trim the boards to size.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome one or more of the
problems described above.
Accordingly, one aspect of the invention is a composite
building component that includes a non-planar molded composite web having
two outer zones and two angled zones wherein the caliper of the angled
zones differs from the caliper of at least one of the outer zones, and a
flange
disposed on an outer surface of an outer zone.
Another aspect of the invention is a composite building
component including a web having at least one channel defined by a first
outer zone, a second outer zone, and at least two angled zones, each of the
zones having a caliper, and each of the zones having inner and outer
surfaces; a first flange joined to the web at an outer surface of the first
outer
zone; a second flange joined to the web at an outer surface of the second
outer zone; wherein the width of the building component. measured in a
direction parallel to a channel, is not greater than the thickness of the
building component, said thickness measured as a distance between parallel
outer surfaces of the flanges.
Still another aspect of the invention is a composite building
component including a non-planar, molded array of wood strands defining a
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-5-
web panel having a caliper and having first and second undulating principal
surfaces, the surfaces providing an alternating pattern of first and second
sets
of ridges extending parallel to each other and oppositely disposed with
respect to a center line of the web panel, adjacent ones of the ridges in the
first set being connected to intermediate ones of the ridges in the second set
by sloped walls, and the caliper of the web panel between the first and
second principal surfaces being different in the vicinity of at least one of
the
first and second sets of ridges as compared to the sloped walls.
Yet another aspect of the invention is a method of producing a
composite building component including the steps of: (a) forming a mat
including a wood-based material; (b) providing the mat in a die set, the die
set having a non-planar configuration with at least two outer zones and at
least two angled zones; (c) closing the die to form a die gap, wherein the die
gap in at at least one of the outer zones differs from the die gap at the
angled
zones; (d) consolidating the mat under pressure and heat to form a molded
composite web; and (e) joining the web with at least one flange, to form the
composite building component.
A further aspect of the invention is a method of producing a
building component including the steps of: (a) forming a mat including an
array of wood strands; (b) providing the mat in a die set, the die set having
a
non-planar configuration with first and second die surfaces; (c) closing the
die to form a die gap, wherein the die gap provides an alternating pattern of
first and second sets of ridges extending parallel to each other and
oppositely
disposed with respect to a center line of the die set, wherein adjacent ones
of
said ridges in the first set are connected to intermediate ones of the ridges
in
the second set by sloped walls formed by the die gap, and wherein the die
gap between the first and second die surfaces is different in the vicinity of
at
least one of the ridges as compared to the sloped walls; (d) consolidating the
mat under pressure and heat to form a molded composite web panel; and (e)
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-6-
joining the web with at least one flange, to form the composite building
component.
Other objects and advantages of the invention may become
apparent to those skilled in the art from a review of the following detailed
description, taken in conjunction with the drawings and the appended claims.
While the invention is susceptible of embodiments in various forms,
described hereinafter are specific embodiments of the invention with the
understanding that the disclosure is illustrative, and is not intended to
limit
the invention to the specific embodiments described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an isometric view of a composite building
component in accordance with the invention which may serve as a wall or
floor system, and which can be divided to provide multiple lumber or post
components.
Figure 2 is a cross-sectional view of a die set used to mold a
web panel embodiment of the invention.
Figure 3 is a cross-sectional view of a web panel embodiment
of the invention.
Figure 4 is an isometric view of a web panel embodiment of
the invention.
Figure 5 is a side elevation with portions removed of a web
panel and flange panels used in an embodiment of the invention and having
textured surfaces.
Figure 6 is a side elevation of a segment of web panel used in
an embodiment of the invention.
Figure 7 is a cut-away isometric view of a portion of a
composite nominal 2x4 lumber component embodiment of the invention.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-7-
Figure 8 is a fragmentary isometric view of a composite
support post embodiment of the invention.
Figure 9 is a fragmentary isometric view of a composite
nominal 2x4 lumber component embodiment of the invention.
Figure 10 is a fragmentary isometric view of a composite
nominal 2x6 lumber component embodiment of the invention.
Figure 11 is a cut-away isometric view of a composite decking
component embodiment of the invention shown with conventional joists or
trusses.
Figure 12 is a top plan view of a molded element used in a
composite decking component embodiment of the invention.
Figure 13 is a side elevation of a molded element used in a
composite decking component embodiment of the invention.
Figure 14 is a cut-away isometric view of a flooring
component embodiment of the invention.
Figure 15 is a side elevation of a tapered segment of web
panel used in an embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
According to the present invention, there is provided a
method and apparatus for producing multi-ply or multi-layered composite
building components from wood-based materials. The wood-based materials
can be, for example, flakes, wafers, particles, fibers, and/or strands,
including mixtures thereof. Generally, the building components can be
provided by coating or spraying one or more wood-based materials such as
flakes or fibers with a resin binder and optionally with a wax and other
performance-enhancing fillers to form the composite raw material or furnish.
The composite raw material or furnish is formed into a mat of generally
uniform basis weight. The mat is loaded into a die set having a desired
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-8-
geometry and consolidated in a heated press to form a composite panel. A
die set used to produce a molded or contoured composite panel is described
below in detail. One or more of these panels is bonded with a second non-
planar or planar flange, and optionally with one or more end blocks or other
framing members, to produce a multi-ply wood composite product of the
invention. In a preferred embodiment of the invention, the bonded assembly
is subsequently cut into multiple multi-ply wood composite building
components.
The multi-ply composite building components of the invention
preferably include OSB components made from a raw material obtained by
breaking down logs or other source of wood into strands, as described
above. Various methods of producing these strands are known in the art.
The strands preferably are produced through mechanical slicing and flaking.
Exemplary sources of wood materials are: aspen, balsam fir, beech, birch,
cedar, elm, locust, maple, oak, pine, poplar, spruce, or combinations
thereof. Aspen or pine is preferred, but the wood used will depend upon
availability, cost, and special use requirements. The type of wood-based
material used will define the type of board and properties produced. For
example, the invention can include components defined as flakeboard,
waferboard, strandboard, OSB, and/or fiberboard. Oriented strandboard is
preferred.
Ranges of exemplary and preferred dimensions of strands for
use in a preferred composite panel are described below in "I'able I.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-9-
Table I - Preferred Strand Dimensions
Length Width Thickness
Exemplary range about 2 inches to about 1/4 inch to about 0.007 inch to
about 10 inches about 3 inches about 0.05 inch
(about 5 cm to (about 6 mm to (about 0.18 mm to
about 25.4 cm) about 76 mm) about 1.27 mm)
Preferred range about 4 inches to about '/z inch to about 0.015 inch to
about 6 inches about 1'/2 inches about 0.03 inch
(about 10 cm to (about 12.7 mm to (about .38 mm to
about 15 cm) about 38 mm) about .76 mm)
Once produced as described above, the strands preferably are
processed to reduce the level of fine particles and dust. This step preferably
is achieved by sending the strands through a rotary screen classifier or by
other suitable means. In general, the level of fines can be up to about 60
weight percent (wt. %) (based on total weight of the wood-based material) at
an about 1/8 inch (about 3.2 mm) screen size or finer, and more preferably
in a range of about 20 wt. % to about 30 wt. %. (Unless otherwise noted,
the percentages expressed herein are based upon weight.) The mixture of
wood-based material is sometimes referred to simplv as wood strands.
The moisture content of the processed strands preferably is in
a range of about 2 wt. % to about 9 wt. %, and more preferably in a range
of about 4 wt. % to about 6 wt. %, based on the weight of the wood-based
material.
The strands (and any accompanying particles and dust) then
are mixed in a blending operation, preferably adding a resin binder, wax,
and any other desired performance-enhancing additives, to form the
composite raw material used to produce the boards of the invention.
Preferred resin binders include phenolic resins, resorcinol resins, and MDI
resins, although any suitable resin can be utilized. Preferably, the resin
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
10-
content is in a range of about 1 wt. % to about 10 wt. % of the weight of the
wood-based material, and more preferably in a range of about 3_5 wt. % to
about 5.5 wt. %. When using MDI resins, less resin is generally required
than when using phenolic or resorcinol resins. In addition to allowing for
reduced resin usage, use of an MDI resin allows for decreased press
temperatures (resulting in reduced energy input) and permits the use of raw
materials with higher moisture contents.
Ingredients can be added to the raw material to impart various
beneficial properties to the composite building components of the invention.
For example, fire retardants, insecticides, fungicides, water repellants,
ultraviolet radiation (UV) blockers, pigments, and combinations thereof can
all be used in alternative embodiments of the invention. An exemplary fire
retardant is sold under the trademark D-BLAZE by Chemical Specialties,
Inc., of Charlotte, N.C. Wax preferably is added to improve moisture
resistance, preferably in a range of about 1/2 wt. % to about 2 wt. % of the
weight of the wood strands, for example at about I wt. %. An exemplary
wax is sold under the trademark EW 58 LV by Borden of Diboll, TX.
The raw material then is continuously deposited on a forming
line to form a mat of generally uniform basis weight. In another
embodiment of the invention, the mat can be formed individually in a batch
process. The basis weight of a mat is calculated as the volume of the molded
panel multiplied by the target density of the molded panel divided by the
surface area of the formed mat, and has units lb/ftz or kg/m2.
The individual, strands in the mat can be imparted a selected
orientation (generally in the case of OSB), or the mat can be assembled with
strands in random orientation. OSB generally refers to a board produced
from a mat wherein the strands are imparted with a selected orientation, but
can also refer to a board produced from a mat wherein the strands are
imparted with or have a random orientation. Individual strand layers within
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-il-
a single mat can, but need not, have different orientations. The strand
orientation affects the mechanical performance characteristics of the
consolidated composite board, so the preferred strand orientation will differ
from application to application.
A continuously-formed mat is then cut to size, having a length
and width roughly equal to, or slightly larger than, the length and width of a
desired panel produced by a suitable die set. Thus, a consolidated panel is
limited in length and width only by the size of the equipment used to produce
the panel.
The mat is then loaded into a die set having the desired
geometry. The temperature of the press platens and die set during mat
consolidation using a phenolic resin preferably is in a range of about 420 F
to about 480 F (about 215 C to about 249 C), and more preferably about
450 F (about 232 C). As will be apparent to those of skill in the art,
desirable pressing temperatures and pressures can be modified according to
various factors, including the following: the die geometry; the type of wood
being pressed; the moisture content of the raw material; the press time; and
the type of resin that is utilized. The moisture content of the raw material
is
one important factor which controls the core temperature of the mat that can
be achieved under given press conditions and therefore may control the press
cycle. Press time can generally be decreased by increasing press
temperature, with certain limitations as is known in the art.
Steam injection pressing is a consolidation step that can be
used, for example, under certain circumstances in production of consolidated
cellulosic composites. In steam injection pressing, steam is injected through
perforated one or more heating press platens and/or dies, and then into,
through, and then out of a mat. The steam condenses on surfaces of the raw
material and heats the mat. The heat transferred by the steam to the mat as
well as the heat transferred from the press platens and/or die set to the mat
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
- 12-
cause the resin to cure. When compared with conventional pressing
operations, steam injection pressing can, under certain circumstances,
provide a variety of advantages, such as, for example, shorter press time, a
more rapid and satisfactory cure of thicker panels, and products having more
uniform densities.
According to an embodiment of the inventive method, a first
mat is consolidated under heat and pressure in an apparatus configured to
produce a molded composite web having one or more contoured features
(e.g., features referred to as ridges, ribs, channels, projections, flat
zones,
upper zones, outer zones, raised zones, or sloped walls), including features
upwardly and/or downwardly disposed from a center line or major planar
surface of the panel, as described below in greater detail. The compressed
panel can be referred to as a molded array of raw material, such as a molded
array of wood strands. The projections preferably are evenly spaced apart.
Upon pressing, the panel retains integritv and does not fracture. The panel
is then edge-trimmed to size.
Preferred embodiments of the inventive articles generally
include multiple OSB components which may or may not have the same
configuration and composition. Thus, one or more additional mats are each
consolidated under heat and pressure in an apparatus configured to produce a
panel having a desired configuration. These additional composite panels can
be flat or can have molded or contoured features, and are likewise edge-
trimmed to size. These additional composite panels are also described in
greater detail below.
One or more of the additional panels are aligned and bonded
with the first panel, and optionally with end blocks or other framing
members, to form a wood composite building component of the invention.
Any suitable adhesive can be used to bond the panels and optional end blocks
with each other. A preferred bonding adhesive, applied at the interfaces
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
- 13-
an/or joints between panels, will provide a shear strength that is at least
about equal to the shear strength of the composite panels themselves. A
preferred bonding adhesive can be selected from the group consisting of hot
melt polyurethane, moisture curing hot melt polyurethane, moisture curing
polyurethane adhesives, and combinations thereof. The adhesive preferably
is applied at a rate in a range of about '/ oz./ftz of contacting surface area
(about 7.4 ml/cm2) to about 3/4 oz./ft2 (about 22 ml/cm'-), for example about
112 oz./ftz (about 14 ml/cm2). In an alternative embodiment of the invention,
waterproof resorcinol adhesives or an isocyanate or MD1-based adhesive can
be used. In another alternative embodiment, the glue can either be replaced
with or assisted by mechanical fasteners, such as staples.
In a preferred embodiment of the invention, the bonded
assembly is subsequently cut into multiple wood composite building
components, as described below.
The advantageous properties of the inventive product allow it
to be an excellent component in construction applications such as lumber
components, floors, walls, roofs, and framing members. This process
according to the invention produces a composite component that integrates
an engineered combination of various desired properties useful in building
components such as compressive and bending strength, bending stiffness,
impact deflection, and increased resistance to water, insects, bacteria, and
fire.
Various preferred embodiments of the invention will now be
described in more detail.
COMPOSITE LUMBER
The inventive process can be used to produce a composite
lumber product of the invention suitable as a replacement for conventional
lumber, or an embodiment engineered with dimensions and strength
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
- 14-
characteristics for specific applications not suitable for conventional
lumber.
Referring initially to Figure 1 for an overview of a product produced in
accordance with the invention, these inventive multi-ply composites involve
a bonded assembly 20 as an intermediate component. The component 20
includes one or more web panels 21 (one shown), and one or more end
blocks 22 (two shown) sandwiched between two flanges 23 (two shown).
The flange 23 in Figure 1 is a flat panel, but this need not be the case. The
bonded assembly 20 preferably is cut in a direction perpendicular to channels
24 in the web panel 21 along lines 25 to produce individual multi-ply wood
composite lumber components of the invention (see Figures 9 and 10), each
composite lumber component having one or more webs 21, flanges 23, and
optional end blocks 22.
It is to be understood that the terms web, flange, and end
block are used to refer to these individual components either as panels and
beams in the bonded assembly 20 or as elements of the individual lumber
components produced by dividing the bonded assembly 20 along lines 25, as
described above and shown in Figure 1. Thus, for example, although the
terms web and web panel are interchangeable, the term web panel can be
used to emphasize a relatively larger sized element, e.g., element 21 in
Figure 1, prior to being divided as described herein.
A method of producing one embodiment of a web panel 21
will now be described with respect to a composite lumber embodiment of the
invention. It is to be understood, however, that the characteristics of the
web panel 21 and its method of manufacture are equally applicable to a web
panel 21 used alone in certain applications and in applications with
additional
components, including the other embodiments of the invention described
later, such as, for example, a decking component.
In a preferred method of producing a composite lumber
product of the invention, the mat which will become the web panel 21 is
CA 02604613 2007-10-23
.' =~
WO 01/75245 PCT/US00/27575
- 15-
formed of up to three layers of resin-coated, loosely felted, oriented strands
in the continuous process described above. The mat can be referred to as
comprising an array of wood strands. For example, a first, or bottom, layer
is formed in the direction parallel to the longitudinal axis of a finished
lumber component. This first layer preferably constitutes about 1/3 to about
100% of the total mat weight. A second, or middle, layer can be formed
perpendicular to the direction of the first layer and can comprise up to about
1/3 of the total mat weight. A third, or top, layer can be formed parallel to
the first layer and can constitute up to about 1/2 of the total mat weight. In
other words, from one to three layers preferably are included in the mat,
wherein each layer generally has strands oriented in a direction
perpendicular to the strands in an adjacent layer. In one preferred
embodiment, each layer comprises about 1/3 of the total weight of the mat.
In another preferred embodiment, about 80% to about 100%
of the strands are oriented in the direction parallel to the longitudinal axis
of
a lumber component, for example about 90% of the strands. In one version
of that embodiment having three layers, the strands oriented in the direction
parallel to the longitudinal axis of a lumber component are distributed
approximately equally, e.g., by weight, between the top and bottom layers
of the mat. In another version of such an embodiment having multiple
layers, the strands oriented in the direction parallel to the longitudinal
axis of
a lumber component are distributed approximately equally by weight
throughout all layers of the mat.
In one preferred embodiment, the dimension of the web panel
21 in the direction perpendicular to the channels 24 roughly corresponds to
the desired length of a completed composite lumber product of the invention.
In another preferred embodiment, the dimension of the web panel 21 in the
direction perpendicular to the channels is less than the desired length of the
completed composite lumber component of the invention to provide space for
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-16-
end block beams 22, as in the embodiment of Figure 1. In such a case, the
web panel 21 preferably is bonded to the flange 23 in such a manner as to
leave an approximately equivalent gap at opposing ends of the bonded
assembly 20 along lines 25. These embodiments are discussed in more detail
below in conjunction with the end blocks 22.
The width of the web panel 21 (i. e. , in the direction
perpendicular to the lines 25) and, thus, the mat used to produce web panel
21, preferably is as great as possible in order to maximize the efficiencies
of
production of multiple lumber components from one bonded assembly 20.
For example, in a 4 foot (about 1.2 m) by 8 foot (about 2.4 m) heated press
used to produce composite lumber about 8 feet (about 2.4 m) long, the web
panel 21 preferably is about 4 feet (about 1.2 m) wide. Most preferably, an
8 foot (about 2.4 m) by 24 foot (about 7.3 m) heated press is used to produce
composite lumber about 8 feet (about 2.4 m) long, with a web panel 21
preferably about 24 feet (about 7.3 m) wide (i. e. , in the direction
perpendicular to the lines 25).
A preferred process for producing an inventive composite
lumber article will now be described. Referring to Figure 2, a loosely felted
web mat (not shown), produced as described above, is loaded into a die set
26 having a preferred unique configuration for producing a web panel 21
having parallel channels 24 with sloped walls. The die set 26, including a
first (upper) die 27 and a second (lower) die 28, determines the profile
geometry of the consolidated web panel 21 _
As the die set 26 is closed on the mat, the wood strands of the
mat preferably shift or slide within the matrix of the mat (or, in one
embodiment of the invention, within the array of wood strands), grossly
conforming to the die configuration. It has been found that, due to
compressing and shearing forces on the mat created by the interaction
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
- 17-
between the upper die 27 and the lower die 28, the surface area of the mat
can increase as much as 75 percent, preferably about 15 to about 25 percent,
most preferably about 20 percent. Because of the unlocked state of the
strands in the loosely felted mat, they generally tend to shift at certain
regions of the mat during the compression operation. Factors influencing the
amount that the surface area of a mat may increase during pressing using the
process of the invention include: the geometry or contours of the web panel
21 (or, in other words, the contours or profile of the web panel 21); the
variation in caliper among various locations of the web panel 21 (or, in other
words, the variation in die gap among various locations of die set 26); the
mat basis weight and orientation of the strands prior to press closure; and
the
strand geometry (including physical length, width and thickness). These
factors affect the ability of the strands to shift or slide within the matrix
of
the mat before bypassing, fracturing, or destroying the continuity of the
composite mat during press closure. The process used and the unique die
configuration used according to the invention help to optimally combine
these factors so that the surface area of the mat can increase without
fracturing the mat, especially at the outer zones 33. At the same time, the
process preferably provides a product with at least substantially uniform
density, resulting in increased strength of the molded board and of objects
constructed therefrom. In contrast, compressed products of prior methods
have been characterized by undesirable density variations. resulting in
reduced strength of a molded board and of objects constructed therefrom.
The temperature of the press platens and/or die set during mat
consolidation using a phenolic resin preferably is in a range of about 420 F
to about 480 F (about 215 C to about 249 C), and more preferably about
450 F (about 232 C). The pressing time depends on the caliper of the
finished product and the other factors listed above, but is generally in a
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
-18-
range of about 1 minute to about 5 minutes in preferred embodiments of the
invention.
The caliper of a consolidated web at any particular point is
defined by a distance or gap between the first die 27 and second die 28
during pressing and consolidation of a mat. For example, the die gap at one
location of the die set 26 is defined by the distance between point 29 and
point 30 in Figure 2. Another measurement of die gap can be made, for
example, at points 31 and 32. As the result of specified variations in the die
gap, the die set 26 of the invention preferably produces a web panel 21
having a caliper that varies from one point to another (e.g.. differing at the
locations of the web corresponding to locations 29/30 and 31/32 of the die
set 26 of Figure 2) to achieve an at least substantially uniform density
throughout the web pane121. This aspect of the invention not only
maximizes the stiffness properties of the web 25, but also maintains the
integrity of the mat during compression.
Figure 3 illustrates the cross-sectional geometry of a web
panel 21 of the invention produced by the die set 26 of Figure 2. Figure 4
provides an isometric view of the web panel 21 produced by the die set 26.
(Like reference numbers in the figures refer to like elements.) The web
panel 21 shown in Figures 3 and 4 has (a) multiple generally planar
longitudinally extending outer zones 33 and (b) multiple longitudinally
extending inner or angled zones 34 that are disposed between, contiguous
with, and integrally formed with the outer zones 33. The outer zones 33 are
disposed upwardly of (e.g., elements 33a, 33b, and 33c in Figure 3) and
downwardly of (e.g., elements 33d, 33e, and 33f in Figure 3), contiguous
with, and integrally formed with the angled zones 34. Preferably, the
intersection of the outer zones 33 with the angled zones 34 is radiused. An
upper surface of the web panel is formed by contact with the first die 27, and
a lower surface of the web panel is formed by contact with the second die
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-19-
28. When the web 21 includes a set of upwardly disposed outer zones (e.g.,
zones 33a. 33b, and 33c) and a set of downwardly disposed outer zones
(e.g., zones 33d. 33e, and 33f), preferably the adjacent outer zones (e.g.,
zones 33a and 33d) are spaced apart laterally a predetermined distance and
vertically a predetermined distance.
Preferably, the caliper of the web 21 at the upwardly disposed
outer zones 33a, 33b, and 33c (as shown in Figure 3) is less than (thinner
than) the caliper of the web 21 at the angled zones 34. The caliper of the
web 21 at the downwardly disposed outer zones 33d, 33e, and 33f preferably
is greater than the caliper of the web 21 at the upwardly disposed outer
zones 33a, 33b, and 33c, and is at least about equal to the caliper of the web
21 at the angled zones 34_ Preferably, the caliper of the web 21 at an
intersection between an outer zone 33 and an angled zone 34 transitions
gradually between the caliper of the web 21 at each of the respective zones
33 and 34, most preferably via a radiused intersection. These calipers are
provided by setting the die gap, as described above. More specifically, the
ratio of the caliper of the upwardly disposed outer zones 33a, 33b, 33c to the
caliper of the angled zones 34 and downwardly disposed outer zones 33d,
33e. 33f preferably is in a range of about 0.75 to about 1.0, and more
preferably is in a range of about 0.8 to about 0.9, for example about 0.85.
The differing calipers provide substantial and unexpected advantages in
production and use of the web 21 in the building components of the
invention.
In one preferred embodiment, the caliper of the web tapers
(for example, by linear decrease in caliper) from a thicker downwardly
disposed outer zone (e.g., zone 33d in Figure 3), through an angled zone
(e.g., zone 34), to a thinner upwardly disposed outer zone (e.g., zone 33b),
wherein the taper extends through the junctions between the various zones.
The die gap at the various zones is adjusted to account for the redistribution
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-20-
of raw material in the mat caused by gravity and the closing of the die set 26
so that the web 21 after formation has a substantially uniform density. Thus,
the caliper of the web 21 preferably is relatively larger where more raw
material is distributed in the die gap, for example in the vicinity of
locations
29/30 in Figure 2, than where less material is distributed in the die gap, for
example in the vicinity of locations 31 /32.
In a composite lumber embodiment of the invention, the
caliper of the web 21 preferably is in a range of about 1/8 inch to about 1
inch (about 3.18 mm to about 25.4 mm), more preferably in a range of about
1/4 inch to about 'h inch (about 6.35 mm to about 12.7 mm). The caliper at
the outer zones 33a, 33b, 33c preferably is in a range of about 0.215 inch to
about 0.465 inch (about 5.5 mm to about 11.8 nun), while the caliper at the
outer zones 33d, 33e, 33f preferably is in a range of about 0.250 inch to
about 0.50 inch (about 6.35mm to about 12.7mm).
The web panel 21 according to the invention preferably has a
specific gravity in a range of about 0.6 to about 0.9 at any location in the
panel, more preferably about 0.65 to about 0.75, most preferably about 0.75
when using southern yellow pine as the cellulosic component in the raw
material. The overall specific gravity of the panel preferably is in a range
of
about 0.6 to about 0.9, more preferably about 0.65 to about 0.75, most
preferably about 0.75 when using southern yellow pine as the cellulosic
component in the raw material, making it a high density wood composite.
The varying die gap preferably allows for the production of a web panel 21
having an at least substantially uniform density throughout its profile.
Preferably, the density of the web 21 at an outer zone 33 is at least about
75 % of the density of the web 21 at an angled zone 34, more preferably at
least about 90%, for example about 95%. Likewise, the density of the web
21 at an upwardly disposed outer zone (e.g., 33a) preferably is at least about
75% of the density of the web 21 at a downwardly disposed outer zone (e.g.,
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-21-
33d), more preferably at least about 80%, most preferably at least about
90 %, for example about 95 %.
Whereas the outer zones 33 of the web panel 21 shown in
Figures 3 and 4 are generally flat (planar), in an alternative embodiment the
outer zones 33 may be curvilinear or may have a combination of curved and
flat surfaces or may have surfaces of other shapes and/or textures. For
example, a texture, contour, or other surface can be provided on outer
surfaces of the outer zones 33 of the web 21 to provide improved interlock
or bonding with other components of the final lumber product, such as a
flange 23, end block 22, or additional web 21. For example, Figure 5
illustrates a portion of a web 21 and flanges 23a and 23b having textured
surfaces 123a 123b. Further, a lower surface 133d of the outer zone 33d has
an alternating ribbed and grooved texture that provides mechanical interlock
and/or grip with ribs and grooves of the surface 123b of the flange 23b. In
one preferred embodiment, the lower surface 133d of the outer zone 33d has
the same texture as the upper surface 123b of the flange 23b, but in other
embodiments the textures can be slightly or completely different. The
texture can include any feature that, when present on one or more surfaces of
a web 21, end block 22, or flange 23, provides improved bonding (e.g.,
grip, frictional resistance, adhesion, or interlock) to a surface of any other
component of a composite building component, with or without the use of an
adhesive. The surfaces 123a, 133a, 133b likewise can be textured to provide
improved bonding as noted above.
Thus, it is understood that the use of the term flat herein
refers to a generally planar portion. In another alternative embodiment, an
outer zone 33 can be the peak of a curved portion of the web 21. In yet
another embodiment, an outer zone 33 can have a caliper that increases or
decreases from the center of the zone 33 to the end of the zone 33 which is
contiguous with, and integrally formed with, an angled zone 34.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-22-
Likewise, the angled zones 34 shown in Figure 3 are
generally flat (planar) (as also shown in Figures 5 and 6), but can also have
contours. For example, a web 21 can have a cross section in the shape of a
sinusoidal curve. In another embodiment, the angled zones 34 shown in
Figure 3 can incorporate one or more flat (planar) zones, for example flat
zones which are substantially perpendicular to the outer zones 33 of the web
21.
The angled zones 34 can form various angles with the outer
zones 33. These angles can be referred to as draft angles. For example,
referring to Figure 6, the angle a between a lower surface 133d of an outer
zone (e.g., 33d) and the centerline 49 of an angled zone 34 is a draft angle
of
the web segment 36. Referring to Figure 15. an embodiment of the web 21
characterized by a tapering caliper in an angled zone 34, the preferred design
has a draft angle P between a surface 133d of an outer zone (e.g_, 33d) and
an upper surface 134a of an angled zone 34. In this case, the angle between
the lower surface 133d of an outer zone (e.g., 33d) and a lower surface 134b
of the angled zone 34 is determined by the selected degree of taper in this
portion of the web 21.
Draft angles a and P of a web 21 preferably are in a range of
about 30 degrees to about 60 degrees, more preferably in a range of about 35
degrees to about 55 degrees, and most preferably in a range of about 40
degrees to about 50 degrees, for example about 45 degrees in a preferred
composite lumber article. In another embodiment of the invention, the draft
angle a or P of a web 21 is greater than 45 degrees. The increased draft
angles, especially draft angles greater than about 45 degrees, provide
substantial advantages in the web panel 21 of the invention, such as the
ability to span greater distances with reduced material cost and increased
strength.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-23-
Referring to Figure 7, there is shown a composite lumber
embodiment of the invention 38 having upper and lower flanges 23a and
23b, respectively, a web 21 sandwiched between the flanges 23a and 23b,
and an optional end block 22. A surface having an outer radius 35 is defined
at an intersection of an outer zone 33 and an angled zone 34 (i.e., a radiused
intersection). This is shown in greater detail in Figure 15 wherein a radius
35a is formed at an intersection of an upwardly disposed outer zone 33a and
an angled zone 34 by the upper surface of the web 21. Such a radius, at an
outer surface of the web 21 (i.e., in the vicinity of an upper surface of an
upwardly disposed outer zone, e.g., 33a, or a lower surface of a
downwardly disposed outer zone, e.g., 33d), can be referred to as an outer
radius or shoulder. Figure 15 shows a radius 35b formed at an intersection
of an upwardly disposed outer zone 33a and an angled zone 34 by the lower
surface of the web 21. Similarly, Figure 15 shows a radius 35c formed at an
intersection of an downwardly disposed outer zone 33d and an angled zone
34 by the upper surface of the web 21. A radius such as radius 35b or 35c at
an inner surface of the web 21 (i.e., in the vicinity of a lower surface of an
upwardly disposed outer zone, e.g., 33a, or an upper surface of a
downwardly disposed outer zone, e.g., 33d) can be referred to as an inner
radius. Preferably, the inner radii (e.g., radius 35b and 35c) are smaller
than the outer radii (e.g., radius 35a). When a web 21 is tapered as in
Figure 15, preferably a radius 35b is smaller than a radius 35c.
A radius 35 of the web 21 generally varies with the overall
caliper of the web 21. For example, the radius 35a of the web 21 at the
intersection between an angled zone 34 and an upwardly disposed outer zone
(e.g., 33a) generally varies with the caliper of the upwardly disposed outer
zone (e.g., 33a). Preferably, the radius 35a dimension is equal to about one
to about three times the caliper at adjacent zones of the web 21. In a
specific
CA 02604613 2007-10-23
=
WO 01/75245 PCT/US00/27575
-24-
embodiment, this dimension is approximately 1.5 times the caliper of the
web 21 at the adjacent outer zone.
Exemplary radii 35a are tabulated in Table 11 below for
various calipers of an upwardly disposed outer zone 33.
Table II - Exemplary Web Radii 35a (Approximate Values)
Caliper of Upwardly Dis osed Outer Zone 33 Radius 35a
0.125 in. (3.175 mm) 0.1875 in (4.76 mm)
0.25 in. (6.35 mm) 0.3125 in (7.93 mm).
0.375 in. (9.525 mm) 0.4375 in (11.1 mm)
0.5 in. (12.7 mm) 0.5625 in (14.3 mm)
0.625 in. (15.875 mm) 0.6875 in (17.5 mm)
0.75 in. (19.05 mm) 0.8125 in (20.6 mm)
The profile thickness or profile depth of the web 21 (measured
by the greatest depth of the web, for example, referring to Figure 5, the
distance from a top surface 133a of zone 33a to a bottom surface 133d of
zone 33d) preferably is in a range of about 1/4 inch to about 8 inches (about
6.35 mm to about 20.32 cm), and more preferably in a range of about 1/4
inch to about 4 inches (about 6.35 mm to about 10. 16 cm).
The depth of draw of a web 21 is measured as the vertical
distance traveled by an angled zone 34 between the center lines of adjacent
outer zones (e.g., the zones 33a and 33d). Whereas the depth of draw can
be uniform throughout a web 21, this need not be the case. Thus, for
example, the top surfaces of the outer zones 33a, 33b, and 33c are
preferably, but optionally, in a single plane. The depth of draw of the web
21 preferably is about 6 inches (about 15.24 cm) or less, and more
preferably in a range of about 1/4 inch to about 31/2 inches (about 6.35 mm
CA 02604613 2007-10-23
r
WO 01/75245 PCTIUSOO/27575
-25-
and about 88.9 mm). In one preferred embodiment of the invention, the
depth of draw of the web 21 is greater than the caliper of any zone.
A web segment 36, depicted in Figure 6, is defined as a
portion of a web 21 between a longitudinal midpoint of a downwardly
disposed outer zone 33 and the longitudinal midpoint of an adjacent
upwardly disposed outer zone 33 (e.g. midpoint of 33d to midpoint of 33b).
This distance, web segment 36 length (measured along the line segment A-B
shown in Figure 6), depends on the draft angle of the angled zone 34, the
depth of draw in the web segment, and the lengths of the downwardly
disposed outer zone 33d and the upwardly disposed outer zone 33b. ln a
web 21 in which all web segments 36 are identical, the frequency of web
segment repeat is defined as the inverse of the length of the web segment 36.
The strength properties of composite lumber articles depends
in part on the frequency of web segment repeat. In general, as the frequency
of web segment repeat increases, the deflection strength of the lumber article
increases. The following design factors interrelate to provide deflection
resistance of a web, and therefore to an article including the web: (a) length
of the lumber desired; (b) width of end block used (if any); (c) draft angle
of
angled zone 34 (which itself depends on the raw material used and the depth
of draw); (d) web caliper at the various zones and intersections of the zones;
(e) web 21 density; (f) area of interface between web 21 and flange 23; and
(g) type and amount of adhesive between web 21, one or more flanges 23 ,
and one or more end blocks 22. These factors can be selected so as to
achieve a desired deflection resistance.
Figure 15 shows another preferred feature of a web 21,
wherein a portion 51 of the lower surface of the web 21 in the vicinity of the
intersection between an angled zone 34 and a downwardly disposed outer
zone (e.g., 33d) is substantially flat (planar) and forms an angle y with
respect to the lower surface 133d of a downwardly disposed outer zone
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
-26-
(e.g.. 33d). This feature can be referred to as a flattened shoulder 51. This
feature permits the caliper of the web 21 to be manipulated or determined at
the intersection of an angled zone 34 and a downwardly disposed outer zone
(e.g., 33d). When incorporating this feature, the intersections of the
flattened shoulder 51 with the surface of an angled zone 34 at one end (e.g.,
the lower surface), and the surface of an outer zone (e. g. , the lower
surface
of downwardly disposed outer zone 33d) at the other end preferably is
radiused.
Preferably the angle y and length of the flattened shoulder 51
are selected to provide a caliper of the web 21 in the vicinity of the
intersection between an angled zone 34 and an outer zone (e.g., downwardly
disposed outer zone 33d) that transitions between the caliper of an outer zone
and the caliper of an angled zone 34. Most preferably, the angle y and
length of the portion 51 are selected to provide a web caliper 21 in the
vicinity of the intersection between an angled zone 34 and an outer zone
(e.g., downwardly disposed outer zone 33d) that corresponds to the
distribution of raw material in the die set 26 in the vicinity of the
intersection
between the angled zone 34 and the outer zone (e.g., 33d) after the die set 26
is closed, to provide a substantially uniform density of the web 21. Thus,
preferably the flattened shoulder 51 feature is used at the intersection of an
angled zone 34 and a downwardly disposed outer zone, e.g., 33d.
The angle y preferably ranges between about 20 and about 50
degrees, and more preferably is between about 25 and about 35 degrees. In
an exemplary embodiment, the angle y is substantially equal to 31 degrees.
In another embodiment of the invention, the consolidated web
panel 21 has first and second undulating principal surfaces, formed by the
first (upper) die 27 and the second (lower) die 28, respectively. The first
and second principal surfaces provide an alternating pattern of first and
second sets of ridges extending parallel to each other and oppositely disposed
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
- 27 -
with respect to a center line of the web panel 21 (e.g., elements 33 in Figure
3). Adjacent ones of the ridges in the first set (e.g., elements 33a, 33b, and
33c in Figure 3) are connected to intermediate ones of the ridges in the
second set (e.g., elements 33d and 33e in Figure 3) by sloped walls (e.g.,
elements 34 in Figure 3), Preferably, at least one principal surface is
radiused in the vicinity of the connection between a ridge and a sloped wall.
The caliper of the web panel 21 between the first and second principal
surfaces is different in the vicinity of at least one of the first and second
sets
of ridges (e.g., elements 33a, 33b, and 33c, and elements 33d, 33e, and 33f
in Figure 3. respectively) as compared to the sloped walls (e.g., elements 34
in Figure 3).
Characteristics of this web panel 21 embodiment of the
invention can be the same as those of the previously-described web panel 21.
For example, in a preferred embodiment, the caliper of the web 21 gradually
increases or decreases from a sloped wall to a ridge via a radiused
connection.
Referring to Figure 1, to create a composite lumber
component one or more consolidated web panels 21 are bonded with two
flange panels 23 and optionally with two end block beams 22 to form the
bonded assembly 20 of Figure 1. In general, the flange panels 23 of a
composite lumber product of the invention can be made from any material.
Exemplary flange materials are: laminated veneer lumber (LVL), solid
conventional lumber, plywood, laminated strand lumber (LSL), parallel
strand lumber (PSL), particle board, OSB, strand board (wafer board),
fiberboard, corrugated board, kraft paper, plastics, fiberglass, and metals.
The flange material optionally can include performance-enhancing materials
such as those described above in relation to the web 21.
The flange 23 also contributes to the deflection resistance of a
composite lumber product. Thus, the flange preferably is made from a
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-28-
material that, in combination with the web, provides the desired deflection
resistance for a particular application. In one preferred embodiment of the
invention, the flanges are OSB, made from the same raw material as the web
21 according to the methods described above. In such an embodiment, the
strands of the flange 23 preferably are oriented in the direction
perpendicular
to the channels 24 of the web 21, and the caliper of the flange 23 preferably
is in a range of about 1/8 inch to about 1 inch (about 3.2 mm to about 25.4
mm). The opposing flanges preferably are of about equal caliper, however,
the inventive articles can use two completely different flanges (both with
respect to caliper and material) in certain applications.
The tlange 23 of the lumber article preferably is generally
planar with a uniform cross-sectional dimension (or caliper). However, it is
to be understood that other flange configurations are useful with the
invention. For example, in one alternative embodiment, a flange 23 itself is
a web 21 having one or more of the characteristics described above. When a
flange 23 is itself a web 21, the term nominal tlange 23 is used to refer to
its
particular web-like properties. Alternatively, such a multi-ply assembly may
be referred to simply as including one or more web 21 panels. Preferably,
such a nominal flange 23 has a relatively small depth of draw [e.g., in a
range of about 1/16 to about 'h inch (about 1.6 mm to about 12.7 mm)J, a
frequency of web segment 36 repeat, and outer zone 33 length sufficient
such that one or more outer zones 33 of the nominal flange 23 comes into
contact with one or more outer zones 33 of the web 21.
Preferably, the flange 23 panels have one dimension, referred
to hereafter as length, which is approximately equal to the length of the
desired composite lumber article. Referring to Figure 1, depicting a bonded
assembly 20, the length of flange 23 panels is measured along lines 25. The
dimension of the flange 23 panels in the planar perpendicular direction
CA 02604613 2007-10-23
.^ ,
WO 01/75245 PCT/US00/27575
-29-
(width) can be any practical size, and preferably is about equal to the width
of the web 21 panel in the bonded assembly 20.
In general, an optional end block 22 of the composite lumber
article of the invention can be made from any material or combinations of
materials, including laminated veneer lumber (LVL), solid conventional
lumber, plywood, laminated strand lumber (LSL), parallel strand lumber
(PSL), particle board, OSB, strand board (wafer board), fiberboard,
corrugated board, kraft paper, plastics, fiberglass, and metals_ Preferably,
the end block 22 is constructed of material of sufficient strength to hold a
mechanical fastener, most preferably of a nailable material. In one preferred
embodiment of the invention, an end block 22 is constructed from
particleboard. In another preferred embodiment of the invention, an end
block 22 is constructed from the offstock of flange 23 production.
Preferably, opposing end blocks 22 are made from the same materials,
however, the invention can include end blocks 22 made from two different
materials or two end blocks 22, each made from different materials.
An optional end block 22 beam preferably has a length
roughly equivalent to the width of the flange panels 23 (which is roughly
equivalent to the width of the web panel 21).
Referring to Figure 1, an optional end block 22 preferably has
a width sufficient to span a predetermined gap between outer edges 223a and
223b of flange panels 23a and 23b and the end of a web panel 21 (not
visible) on each end of the bonded assembly 20. Preferably, the end block
22 is sufficiently large to provide an adequate volume of solid material to
hold a mechanical fastener when the lumber is installed.
Referring to Figures 1 and 5, an optional end block 22 beam
preferably is sufficiently large to span a gap formed between inner faces
123a and 123b of opposing flanges 23a and 23b in the bonded assembly 20.
In a composite lumber article of Figure I wherein the length of a web panel
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-30-
21 in the direction perpendicular to the channels 24 along lines 25 is less
than the length of flanges 23 along lines 25, the end block 22 beam thickness
preferably is about equal to the depth of draw of the web panel 21. In
another embodiment, the length of a web panel 21 in the direction along the
lines 25 is roughly equal to the length of the flange 23 panels (wherein an
outer zone 33 of the web 21 extends to the outer edges 223a and 223b of the
flanges 23). In such an embodiment, a preferred end block 22 has a
thickness about equal to the depth of draw of the web 21. less the caliper of
a terminal outer zone 33. In other words, in such an embodiment the end
block 22 has a thickness no larger than the gap formed between the inner
surface of the outer zone 33 of the web 21 and the inner surface (e.g., 123a)
of the opposing flange 23.
To assemble a preferred intermediate bonded assembly 20,
bonding adhesive is applied to the interfaces between components, and the
components are aligned. For example, adhesive can be applied to the outer
surfaces 133a, 133b, and 133d (Figure 5) of outer zones 33 of one or more
web panels 21. Where two or more web panels are utilized, preferably the
outer zones 33 are aligned such that the channels 24 are parallel and the
outer surfaces of the outer zones 33 coincide, for example as shown in
Figure 10. One or more web 21 panels can be stacked to form the web core,
which can be aligned with one or more flange 23 panels and bonded thereto.
Optional end blocks 22 can be bonded to the flange panels 23 and web
panel(s) 21 at the ends of the web panel(s) 21, parallel to the channels 24. A
second flange panel can be aligned with and bonded to the web 21 panel and
optional end block 22 beams.
Subsequent to application of the bonding adhesive and
alignment of the components, the entire bonded assembly 20 is conveyed
into a press, preferably a continuous nip press or a platen press, for a
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-31 -
predetermined period of time, and subjected to elevated pressure and/or
temperature sufficient to cure and/or dry the adhesive.
To produce a composite lumber article, the bonded assembly
20 is then conveyed to a multiple-arbor saw. The saw cuts the bonded
assembly 20 in the direction perpendicular to the channels 24, along the lines
25. The width between the arbors is about equal to the width of the desired
composite lumber articles, for example about 11h inches (about 3.81 cm),
the width of a nominal 2x4. Using this method, multiple multi-ply wood
composite lumber embodiments of the invention can be produced from a
single bonded assembly 20.
A support post 37, one example of which is depicted in Figure
8, can be produced from the same intermediate bonded assembly 20 used for
composite lumber by simply cutting a thicker section, for example about 1
foot (about 30.5 cm), from the bonded assembly 20, preferably in the
direction parallel to the channels 24. In this manner a support post 37
having a width of about 1 foot (about 30.5 cm) can be produced with the
same efficiencies of composite lumber. This is an advantage over known
methods in which, for example, 8 conventional 2x4's are glued together to
produce a support post with the same dimensions.
Added performance such as coloring and resistance to fire,
insects, bacteria, and water can also be achieved by the addition of suitable
performance-enhancing additives and/or by the application of suitable
specialty coatings to the surfaces of the composite lumber articles of the
invention.
Composite lumber embodiments of the invention can be
designed to have the same outer dimensions as conventional lumber and
modulus of elasticity and moment of inertia sufficient to meet construction
requirements for typical applications. However, the invention is also
applicable to the production of lumber components having alternative cross
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-32-
sectional dimensions, and in lengths limited only by the size of the
equipment used to produce the individual components of the assembly 20.
Furthermore, the invention can also provide composite lumber
articles having performance characteristics that differ from their
conventional lumber counterparts. For example, conventional 2x6 (nominal)
lumber is frequently used in building construction to provide a 5'/2 inch
(about 14 cm) deep space for R-19 insulation between sheathings, but is
typically much stronger than necessary to meet building code requirements,
thereby increasing the cost of a construction project. A multi-ply wood
composite lumber component of the invention nominally measuring 2x6 may
have the same cross-sectional dimensions as a conventional 2x6, but can be
engineered to specific (e.g., increased or decreased compared to
conventional wood lumber) strength requirements. Thus, one advantage of
the invention is the ability to provide a building component that meets or
exceeds the building code requirements but, among other advantages, uses
less starting material, weighs less, and is less expensive to produce than a
conventional article, such as a conventional 2x6.
Example of Nominal 2x4 of the Invention
An example of a preferred composite product of the invention
(shown in an isometric view in Figure 9) suitable as a replacement for
conventional 2"x4"x8' (nominal) conventional lumber includes one web 21
and two end blocks 22 sandwiched between and bonded with two flanges 23.
A preferred composite 2x4 article 38 of the invention is designed to have the
same cross-sectional dimensions as conventional 2x4 lumber, namely 11/2
inches by 31/2 inches (about 38.1 mm by about 88.9 mm), a length of about 8
feet (about 244 cm), and a modulus of elasticity that allows the product to
meet construction and safety standards for Housing and Urban Development
(HUD) manufactured home construction for Wind Zone 1 construction.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
- 33 -
However, the invention is also applicable to the production of other multi-
ply wood composite replacements for conventional lumber, including actual
and nominal lx3s, lx4s, 2x3s. 2x6s. 2x8s. 2x10s. 2x12s, 4x4s, 4x6s, and
6x6s, for example, and in lengths limited only by the size of the equipment
used to produce the individual components of the assembly 20. For
example, Figure 10 is a perspective view of a multi-ply composite 2x6
article 39 which can serve as a replacement for a conventional nominal 2x6.
This embodiment of the invention incorporates two web 21 panels bonded at
their outer zones 33.
The construction of a preferred 2x4 article 38 of the invention
will now be described. A preferred web 21 can be made from strands
having a length in a range of about 41,,z inches to about 51h inches (about
11.4 cm to about 14 cm), width in a range of about 3/4 inch to about 1 inch
(about 19 mm to about 25.4 mm), and thickness in a range of about 0.02
inch to about 0.025 inch (about 0.51 mm to about 0.64 mm). The strands
utilized in a preferred web 21 have a pre-pressing moisture content in a
range of about 2% to about 9%, preferably in a range of about 4% to about
6%, for example about 5%. based upon weight of the strands.
The mat is produced as described above by combining
strands, resin binder, a wax, and other optional additives. A preferred resin
binder for the web 21 is a resorcinol resin, preferably added at about 41/2
wt.
% based upon the weight of the wood strands. Wax preferably is added to
the raw material in a range of about !~, wt. % to about 2 wt. %, for example
about 11/2 wt. %, based upon the weight of the wood strands.
In a preferred 2x4 embodiment, the mat which will become
the web 21 is formed of three layers of raw material including strands,
according to the continuous process described above. The strands of the
first (bottom) and third (top) layers are oriented in the machine direction
(i.e., in the direction perpendicular to channels 24) and comprise about 90%
CA 02604613 2007-10-23
WO Ot/75245 PCT/USOO/27575
-34-
of the total mat weight, divided about equally between the two layers. The
strands of the second, or middle, la-yer are oriented perpendicular to the
machine direction (i.e., in the direction parallel to channels 24) and
comprise
the remainder, about 10% of the total mat weight.
The composite 2x4 articles of the invention preferably are
made having lengths of about 81.75 inches (about 2.08 m), about 87.75
inches (about 2.23 m), or about 96 inches (about 2.44 m), to correspond to
lengths typically used in construction industries. One type of preferred web
21 for use in the above articles has lengths of about 81.75 inches (about 2.08
m), about 87_75 inches, (about 2.23 m) or about 96 inches (about 2.44 m),
respectively. In an alternative web embodiment, the preferred lengths are
about 75.75 inches (about 1.92 m), about 81.75 inches (about 2.08 m), or
about 90 inches (about 2.29 m), respectively to provide an approximately 3
inch (about 7.6 cm) space at each end for end blocks.
The width of the web panel (and, thus, the mat used to
produce the web) preferably is as great as possible in order to maximize the
efficiencies of production of multiple lumber components from one bonded
assembly 20. For example, in a 4 foot by 8 foot (about 1.22 m by 2.44 m)
heated press used to produce composite 2x4 lumber about 8 feet (about 2.44
m) long, the web panel preferably is about 4 feet (about 1.22 m) wide. Most
preferably, an 8 foot (about 2.44 m) by 24 foot (about 7.32 m) heated press
is used to produce composite 2x4 lumber about 8 feet (about 2.44 m) long,
with a web panel preferably about 24 feet (about 7.32 m) wide.
The temperature of the press platens during mat consolidation
using a phenolic resin preferably is about 450 F (about 232 C). The
pressing time depends on the caliper of the finished product and the other
factors listed above, but is generally in a preferred range of about 2.5
minutes to about 3 minutes for a preferred web of the invention for use in
2x4 composite lumber applications.
CA 02604613 2007-10-23
WO 01/75245 PCr/US00/27575
-35-
The web panel 21 according to the invention preferably has a
specific gravity in a range of about 0.6 to about 0.9 at any location in the
panel, most preferably about 0.75. The overall specific gravity of the panel
preferably is in a range of about 0.6 to about 0.9, for example 0.75, making
it a high density wood composite. The varying die gap preferably allows for
the production of a web panel 21 having an at least substantially uniform
densitv throughout its profile. Preferably, the density of the web 21 at an
outer zone 33 is at least about 75 % of the density of the web 21 at an angled
zone 34, more preferably at least about 90%, for example about 95%.
Likewise, the density of the web 21 at an upwardly disposed outer zone
(e.g.. 33a) preferably is at least about 75% of the density of the web 21 at a
downwardly disposed outer zone (e.g., 33d), more preferably at least about
80 %, most preferably at least about 90 %, for example 95 %.
The caliper of the web 21 of the article 38 preferably is in a
range of about 1/4 inch to about 1/2 inch (about 6.35 mm to about 12.7 nun).
The caliper of the angled zones 34 preferably is greater than that of the
upwardly disposed outer zones 33a, 33b, and 33c. The caliper of the
downwardly disposed outer zones 33d, 33e, and 33f preferably is at least
about equal to that of the angled zones 34. For example, in the article 38 of
Figure 9, the caliper of downwardly disposed outer zones 33d, 33e and 33f,
and the angled zones 34 is about 0.375 inch (about 9.52 mm) and the caliper
of the upwardly disposed outer zones 33a, 33b and 33c is about 0.340 inch
(about 8.64 mm). In another example, the caliper of downwardly disposed
outer zones 33d, 33e and 33f is about 0.352 inch (about 8.94 mm), the
caliper of upwardly disposed outer zones 33a, 33b and 33c is about 0.3 inch
(about 7.62 mm), and the caliper of the angled zones 34 tapers from 0.352
inch to about 0.3 inch between the downwardly disposed and upwardly
disposed outer zones, respectively.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-36-
The outer zones 33 of the web 21 preferably have a length of
about 6 inches (about 15.24 cm) or less, or about 2 inches (about 5.08 cm)
or less, for example about 1.1688 inches (about 2.97 cm). The outer zone
33 of the web 21 can be longer than 2 inches in special applications. The
draft angle of the web 21 of the article 38 preferably is about 45 degrees.
Table III below sununarizes preferred dimensions for a
tapered composite lumber web 21 useful as a component of a nominal 2x4,
wherein the web 21 has a profile thickness equal to about two inches (5.08
cm), a web segment 36 length equal to about 3.175 inches (8.06 cm), a draft
angle P equal to about 45 degrees, an angle y in the range of about 25
degrees to about 35 degrees, and radii 35b and 35c each independently
established in a range between approximately 0.15 inches (3.81 mm) and
approximately 0.35 inches (8.89 mm), for example 0.25 inches (6.35 mm).
The caliper of angled zone 34 at three different locations is indicated in
Figure 15 by elements 34a, 34b, and 34c.
Table III - Preferred Web Caliper and Radii, Approximate Values'
Caliper of web 21 at different locations Preferred range Preferred
33a 34a 34b 34c 33d for radius 35a radius 35a
0.125 0.127 0.135 0.143 0.147 0.234 to 0.360 0.297
(3.18) (3.23) (3.43) (3.63) (3.73) (5.94 to 9.14) (7.54)
0.25 0.253 0.269 0.285 0.293 0.469 to 0.719 0.597
(6.35) (6.43) (6.83) (7.24) (7.44) (11.91 to 18.27) (15.09)
0.375 0.380 0.404 0.428 0.440 0.703 to 1.079 0.891
(9.53) (9.65) (10.26) (10.87) (11.18) (17.85 to 27.41) (22.63)
0.500 0.507 0.539 0.570 0.587 0.938 to 1.438 1.188
(12.7) (12.88) (13.69) (14.48) (14.91) (23.83 to 36.53) (30.18)
0.625 0.633 0.673 0.713 0.733 1.172 to 1.796 1.484
(15.88) (16.08) (17.09) (18.11) (18.62) (29.77 to 45.61) (37.69)
0.750 0.760 0.808 0.855 0.880 1.406 to 2.156 1.781
(19.05) (19.30) (20.52) (21.72) (22.35) (35.71 to 54.77) (45.24)
* all dimensions in inches (mm)
CA 02604613 2007-10-23
WO 01/75245 PCT/1JS00/27575
-37-
The flanges 23a and 23b of the article 38 preferably are OSB,
made from the same raw material as the web 21 and oriented with the
strands perpendicular to the channels 24 of the web 21 (i.e., parallel with
the
longitudinal axis of the article 38). The flange 23 preferably has a length of
about 8 feet (about 2_43 m). The caliper (thickness) of the flange 23
preferably is in a range of about 1/8 inch to about 1 inch (about 3.18 mm to
about 25.4 mm), and more preferably in a range of about 1/2 inch to about 1
inch (about 1.27 cm to about 2.54 cm), for example about 0.75 inches (about
1.9 cm) in a preferred flange 23 embodiment useful in a nominal 2x4
embodiment of the invention.
In one preferred embodiment of the invention, the end block
22 width (measured in Figure 1 in the direction parallel to lines 25)
preferably is in a range of about 1 inch (about 2.54 cm) to about 5 inches
(about 12.7 cm), preferably about 11/2 inches (about 3.8 cm), more
preferably about 3 inches (about 7.62 cm). An end block 22 can be
constructed from the offstock of flange 23 production. For example, an end
block with width about 1'/2 inches (about 3.8 cm) can be achieved by
bonding together two segments of 3/4 inch (1.9 cm) flange 23 stock or
offstock, as shown in Figure 9, for example. The end block 22 thickness
preferably is about 2 inches (about 5.08 cm), about equal to the profile depth
of the web 21.
The web panel 21, flange panels 23, and end blocks 22 then
are assembled and bonded according to the method described above to form
a bonded assembly 20, as shown in Figure 1. In a preferred 2x4 article of
the invention produced according to the description above, the bonding
adhesive has a minimum shear strength of about 400 lb/in2 (about 28.1
kg/cm').
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
- 38 -
The bonded assembly 20 then is conveyed to a multiple-arbor
saw. The saw cuts the bonded assembly in the direction perpendicular to the
channels 24 of the web 21 along lines 25 of Figure 1, as described above.
A composite 2x4 of the exaniple is designed to meet
construction specifications for applications in which conventional 2x4s are
used as studs. In a preferred 2x4 embodiment, the flange 23 has a minimum
modulus of elasticity of about 900,000 lb/inz. For example, in a test method
described by Fleetwood Enterprises. Inc., of Riverside, CA and HUD
standards, a nominal 2x4 is supported at the top and bottom (in contact with
the side measuring 11/2 inches (3.8 cm)) and an evenly distributed load is
applied over the length of the component. To pass a "live load" test, a 2x4
does not break inunediately after application of 21/2 times the "live load."
To pass a deflection test, the 2x4 must not be displaced at the midpoint more
than a maximum allowable deflection value. The live load is determined by
the wind load, which is about 15 lb/ft2 (73 kg/mz) multiplied by the length of
the lumber component and multiplied by the distance that the studs are
spaced apart in a wall. The allowable deflection is determined by the 2x4
length divided by 180. For example, for a 2x4 having length of about 81.75
inches (about 2.08 m) and spaced apart about 16 inches (about 40.64 cm),
the live load is about 136 pounds (about 61.7 kg) and the allowable
deflection is about 0.45 inch (about 11.43 mm); for a 2x4 having length of
about 87.75 inches (about 2.23 m) and spaced apart about 16 inches (about
40.64 cm), the live load is about 146 pounds (about 66.3 kg) and the
allowable deflection is about 0.49 inch (about 12.45 mm); and for a 2x4
having length of about 96 inches (about 2.44 m) and spaced apart about 16
inches (about 40.64 cm), the live load is about 160 pounds (about 72.6 kg)
and the allowable deflection is about 0.53 inch (about 13.46 mm).
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-39-
DECKING
The inventive process can be used to produce an integrated
composite decking component product of the invention suitable as a
replacement for conventional decking, or engineered with dimensions and
strength characteristics for specific applications. Figure 11 is a cutaway
isometric view of a two-ply composite decking component 40, shown with
conventional joists or trusses 41. A decking component 40 preferably has a
first (lower) molded decking panel 42 bonded to a second (upper) sheathing
panel 43. The decking panel is one embodiment of the web panel 21
described above, and thus can have the characteristics and properties of the
web panel 21 described above. A preferred decking panel 42 is shown in
Figure 12 in a top plan view, and in Figure 13 in a side elevation. The
portion of the decking panel 42 that is located in the major plane of the
panel
is referred to as the lattice 46.
The decking panel 42 preferably includes at least one cavity
44, preferably one or more rows and/or one or more columns of cavities 44
(shown from the side in Figure 13) depending from, contiguous with, and
integrally formed with a lattice 46 of a wood composite panel. In one
preferred embodiment, shown in Figures 11, 12, and 13, the cavities 44 are
downwardly disposed right rectangular pyramidal frusta. A frustrum is
defined as what remains of a pyramid or cone after truncation along a plane
parallel to the base of the pyramid or cone, and frusta is the plural form of
frustrum. A cavity 44 of the preferred embodiment has angled (or sloping),
spaced-apart side walls 45 extending downwardly from a lattice 46 and
terminating in a substantially planar cavity bottom or floor 47, wherein the
plane of the cavity floor 47 is generally parallel to the major plane of the
lattice 46 of the decking panel 42. The decking component 40 is supported
by and/or attached to joist and/or truss elements 41 at parallel,
substantially
flat strips 46a, 46b, and 46c of the lattice 46 between rows and/or columns
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
-40-
of cavities 44 of decking panel 42. The decking component 40 can be
attached to joist and/or truss elements 41 by any suitable means, including
adhesives and mechanical fasteners, such as staples.
A decking panel 42 of the invention preferably is strand
board, wherein the raw material is formed according to the process described
above. A mat which becomes the consolidated decking panel 42 preferably
is formed of up to three layers of raw material in the continuous process
described above, and then cut to size. The strands in a decking panel 42 can
be randomly oriented or can be imparted with a specific orientation.
Preferabte, the strands in a decking panel 42 are randomly oriented. In
addition, the decking material optionally can include performance-enhancing
materials such as those described above.
In one preferred embodiment, the caliper of the decking panel
42 at the cavity floor 47 and at cavity side walls 45 is greater (thicker)
than
the caliper of the panel 42 at the lattice 46. In apreferred decking panel 42,
the caliper of the cavity floor 47 is at least about equal to the caliper of
the
cavity side walls 45, and the ratio of the caliper of the lattice 46 to the
caliper of the cavity side walls 45 is at least about 0.75, and more
preferably
in a range of about 0.8 to about 0.9, for example about 0.85.
In another preferred embodiment. the caliper of the decking
panel 42 at the cavity floor 47 is less (thinner) than the caliper of the
panel at
the cavity side walls 45 and lattice 46. In such a decking panel, the caliper
of the lattice 46 is at least about equal to the caliper of the cavity side
walls
45, and the ratio of the caliper of the cavity floor 47 to the caliper of the
cavity side walls 45 is at least about 0.75, and more preferably in a range of
about 0.8 to about 0.9, for example about 0.85.
In general, the draft angles formed by the cavity side walls 45
and the lattice 46 of a decking panel 42 are in a range of about 30 degrees to
about 60 degrees, preferably in a range of about 35 degrees to about 55
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
-41 -
degrees, most preferably in a range of about 40 degrees to about 50 degrees.
for example about 45 degrees. In another embodiment of the invention, the
draft angle between a side wall 45 and the lattice 46 of a decking panel 42 is
greater than 45 degrees. The increased draft angles, especially draft angles
greater than about 45 degrees, provide substantial advantages in the decking
component 40 of the invention, such as the ability to span greater distances
with reduced material cost and increased strength.
The profile thickness of a decking panel 42 (measured by the
greatest depth of the decking panel 42, for example, the distance from an
upper surface 146 of the lattice 46 to a bottom surface 147 of a cavity floor
47 preferably is in a range of about 1/4 inch (about 6.35 mm) to about 8
inches (about 20.32 em), and more preferably about 1/4 inch (about 6.35 mm)
to about 4 inches (about 10.16 cm).
The depth of draw is measured as the vertical distance
traveled by a side wall 45 between the center lines of a cavity floor 47 and
lattice 46. Whereas the depth of draw can be uniform throughout a decking
panel 42, this need not be the case. Thus, for example, the cavity floors 47
are preferably, but optionally, in a single plane. The depth of draw
preferably is at most about 6 inches (about 15_24 cm), and more preferably
in a range of about 1/4 inch (about 6.35 mm) to about 31/2 inches (about 8.89
cm). In one decking embodiment of the invention, the depth of draw is
greater than the caliper of any one of the lattice 46, side wall 45, and
cavity
floor 47.
The length of a cavity 44, for example the distance between
parallel flat zones 46a and 46b preferably is in a range of about 6 inches
(about 15.24 cm) to about 90 inches (about 228.6 cm). The width of a
cavity 44, measured in the direction perpendicular to the length, preferably
is in a range of about 4 inches (about 10. 1 cm) to about 24 inches (about
60.9 cm).
CA 02604613 2007-10-23
WO 01/75245 PCTIUSOO/27575
-42-
Whereas the lattice 46 shown in Figures 11, 12, and 13 is
generally flat (planar), in an alternative embodiment the lattice 46 can have
contours or other deviations from a planar configuration. For example, a
texture can be added to the upper surface 146 of the lattice 46 and,
optionally, to the matching surface of the sheathing 43 to provide improved
bonding, as described with respect to composite lumber above. A texture
also can be added to the lower surface of the lattice 46 (i.e., the surface
opposite the upper surface 146) and, optionally, to the matching surface of a
joist and/or truss 41 to provide improved bonding, as described with respect
to composite lumber above.
In a preferred embodiment of the invention, a consolidated
decking panel 42 is bonded with a sheathing panel 43 to form the decking
component 40 shown in Figure 11. In general, the sheathing 43 of a decking
component 40 of the invention can be made from any material. The
sheathing 43 contributes to the deflection resistance of a composite decking
component 40. Thus, the sheathing 43 preferably is made from a material
that, in combination with the decking panel 42. provides the desired
deflection resistance for a particular application. In one preferred
embodiment of the invention, the sheathing 43 is strand board, made from
the same raw material as the decking panel 42. In another preferred
embodiment, the sheathing 43 is particleboard.
A sheathing 43 of the composite decking component 40
preferably is generally planar with a uniform cross-sectional dimension.
However, it is to be understood that the invention is also applicable to the
use of other sheathing configurations.
Preferably a sheathing 43 has a length and width about equal
to the length and width of a corresponding decking panel 42 in the decking
component 40.
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-43-
FLOOR COMPONENTS
The inventive process can be used to produce an integrated
floor component product of the invention suitable as a replacement for
conventional joist and decking flooring, or engineered with dimensions and
strength characteristics for specific applications. Figure 14 is a cutaway
isometric view of a four-ply or four-layer composite floor component 48.
The floor component 48 preferably is made by the same method used to
produce the bonded assembly 20 of the composite lumber embodiments,
optionally without end blocks.
Referring to Figure 14, a floor component 48 produced by the
method of the invention preferably has two web 21 panels bonded to and
sandwiched between two flange panels 23a and 23h. This floor component
48 of the invention provides significant advantages over the prior art,
including reduced cost and reduced labor needs for installation.
WALL COMPONENTS
The inventive process can be used to produce an integrated
wall component product of the invention suitable as a replacement for
conventional stud and sheathing walls, or engineered with dimensions and
strength characteristics for specific applications.
The wall component preferably is made by the same method
used to produce the bonded assembly 20 of the composite lumber
embodiments. The web 21 of a wall component preferably has a much
lower frequency of web segment 36 repeat. In addition, the wall component
preferably has one web 21 with a profile depth of about 51h inches (about 14
cm) to accommodate R-19 insulation in the channels 24 between flanges 23.
Building components made according to the invention such as
lumber components, decking components, tloor components, walls, posts
and framing members exhibit many improved attributes. First, the invention
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
-44-
provides consistency in sizing accuracy of building components, both at the
time of construction and over the lifespan of the component and structures
built therewith. The building components of the invention also require less
material input than their conventional lumber and sheathing counterparts.
The building components of the invention can weigh less than their
conventional lumber and sheathing counterparts. Because the building
components of the invention weigh less than their conventional lumber and
sheathing counterparts, they can be shipped in larger sizes. Moreover,
because the building components of the invention are dimensionally
consistent and can be shipped in larger sizes, less labor is required to
assemble the components in construction of a building. In addition, the
invention can provide a product with increased surface friction to facilitate
installation and usage.
Larger distances can be spanned while using fewer supporting
members because the building components of the invention can be
engineered to be stronger than their conventional lumber counterparts. The
composite lumber embodiments of the invention are able to provide built-in
voids suitable to accommodate wiring and piping, which eliminates the labor
involved in drilling conventional lumber for the same purpose. Moreover,
the multi-ply building components of the invention are able to provide built-
in voids which increase the thermal and acoustic insulating efficiency of the
components. The invention also provides for the ability to engineer building
components with built-in properties such as custom pigmentation and
resistance to fire, insects, water, UV radiation, and bacteria. The building
components of the invention also are environmentally friendly because they
allow for more thorough usage of timber, allow for the usage of lower-
quality timber, and can be ground up and easily disposed of or reused.
Finally, the invention provides for great efficiencies of production whereby
many pieces of composite lumber or fully-assembled flooring svstems can be
CA 02604613 2007-10-23
WO 01/75245 PCT/US00/27575
- 45 -
produced at once in assembly-line fashion and whereby many of the same
operations can be used to produce different building components such as
walls, posts, and composite lumber.
The foregoing detailed description is given for clearness of
understanding only, and no unnecessary limitations should be understood
therefrom, as modifications within the scope of the invention will be
apparent to those skilled in the art.
