Note: Descriptions are shown in the official language in which they were submitted.
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ENGINEERED PLANK AND ITS MANUFACTURING METHOD
BACKGROUND
[0001] The invention relates to building materials, predominantly flooring,
especially
involving an engineered plank and its production method. In a common approach
to
constructing flooring planks that have some plastic content, a substrate is
extruded and then a
surface layer is glued to the substrate. Typically, to create a desired look,
the surface layer is
a composite layer comprising a printed paper sheet glued to a wear layer.
Then, to make a
flooring plank, after gluing the wear layer and the drawing paper to form the
surface layer
and extruding and forming the substrate, these are compressed and pasted
together.
[0002] Flooring planks are commonly made using wood or wood byproducts. For
example,
wood-plastic composite (WPC) engineered planks have a composite substrate
having different
layers of different materials that are in turn glued together to form the
substrate. For
example, a WPC plank might be constructed by extruding a wood polymer
composite skin,
extruding a low-density polymer core layer and gluing the skin and the core
layer to form the
substrate, and then gluing the surface layer to the substrate. This is often
needed to increase
the plank's rigidity.
[0003] In a typical construction process, the substrate, whether it is a
single-layer substrate
or a multi-layer substrate, is cut into slabs, such as 4 foot by 8 foot slabs,
as is the surface
layer. These are then aligned, glued, and with a high-pressure press, are
pressed together.
[0004] The slabs might then be further cut and suitable edge connectors cut
into the edges.
A slab or plank can be constructed from a core that is adhered to a wear layer
and possibly
other layers using adhesive. A wear layer might be made separate from the
substrate and later
adhered with a waterproof adhesive.
[0005] The WPC substrate uses wood powder, which can result in a waste of
resources, as
it can affect the finish of the goods or create mustiness. WPC flooring planks
might also
require a coating process, which may increase the required number of
processing steps and
may make continuous production more difficult.
[0006] Therefore, improved engineered planks and improved methods for
manufacturing
engineered planks may be desired.
SUMMARY
[0007] In embodiments, an improved engineered plank is provided that overcomes
some of
the shortcomings of existing WPC and vinyl plank technologies. A plank is
described and a
method for manufacturing the plank. The plank can be produced by mixing
polyvinyl
chloride powder, coarse whiting and light calcium compound powder, stabilizer,
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polyethylene wax, internal lubricant, plasticizer, and impact modifier
together, and stirring or
blending this mixture. The mixture is then extruded through an extruder
compound to form a
plastic composite base material. A surface layer is then fused onto the
plastic composite base
material using thermal compression, without the use of intermediate adhesive
materials.
[0008] In some embodiments, a core of the plank is High Density Plastic
Composite
(HDPC) and can have a density of around 1.9 tons/m3 (tons per cubic meter).
The plank has
a rigid core construction and uses no glue or binders.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a diagram of a structure of an engineered plank.
[0010] FIG. 2 is another diagram of a structure of an engineered plank.
[0011] FIG. 3 is another diagram of a structure of an engineered plank.
[0012] FIG. 4 is a diagram illustrating a process for embossing in
registration as part of an
extrusion process.
[0013] FIG. 5 is a schematic diagram of a production system for manufacturing
the
engineered planks.
[0014] FIGs. 6A and 6B illustrate elements of FIG. 5 in expanded views.
[0015] FIG. 7 is a schematic diagram of a roller system of the production
system of FIG. 5
shown in greater detail.
[0016] FIG. 8 is a graph showing flatness of Test Sample 1.
[0017] FIG. 9 is a graph showing flatness of Test Sample 2.
[0018] FIG. 10 is a graph showing flatness of Test Sample 3.
[0019] FIG. 11 is a graph showing flatness of Test Sample 4.
[0020] FIG. 12 is a cross-sectional view of the flatness graph of Test Sample
1.
[0021] FIG. 13 is a cross-sectional view of the flatness graph of Test Sample
2.
[0022] FIG. 14 is a cross-sectional view of the flatness graph of Test Sample
3.
[0023] FIG. 15 is a cross-sectional view of the flatness graph of Test Sample
4.
DETAILED DESCRIPTION
[0024] In the following description, for purposes of explanation, numerous
examples and
specific details are set forth in order to provide a thorough understanding of
the present
disclosure. It will be evident, however, to one skilled in the art that the
present disclosure as
expressed in the claims may include some or all of the features in these
examples, alone or in
combination with other features described below, and may further include
modifications and
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equivalents of the features and concepts described herein. The present
disclosure provides
additional detail to be read with the appended figures.
[0025] As described above, existing WPC flooring plank technology has a number
of
limitations. Accordingly, plank technology that addresses these limitations is
desired. For
example, it may be advantageous to construct a plank that does not use certain
adhesive
products, such as glue, and which do not use wood powder in the core.
[0026] These limitations may be overcome by using an engineered flooring plank
using a
High Density Plastic Composite (HDPC) or Rigid Core plank as described herein
as the
substrate. Such planks may allow for additional density and resistance to
indentation when
compared to existing WPC planks. For example, some WPC planks might have a
density of
0.85 tons/m3 while the HPDC has a density of 1.9 tons/m3 or in a range of
around that
density, such as 1.7 to 2.1 tons/m3. Additionally, manufacturing these planks
may not require
the use of any glue, which may lead to higher quality products, since a hot
glue melt can
result in an adhesive breakdown and may delaminate the plank. One technique
used to create
improved engineered floor planks may be referred to as a co-extrusion and a
continuous-press
process (CPP).
[0027] The substrate for the engineered planks is formed by heating the
materials used to
form the substrate and extruding the substrate, such as by using a three-
calender roller. The
surface layer is applied to the substrate during extrusion such that the
action of the extrusion
compresses the surface layer and the substrate together. As the substrate is
hot, the surface
layer will adhere to the substrate without requiring glue. Where the surface
layer and/or the
substrate comprise more than one layer, those layers can be combined in the
extrusion
process.
[0028] The surface layer of such a plank may be constructed from many
different types of
materials, and can include one or more of ceramic, tile, glass, rubber,
plastic, paper, leather,
metal materials, stone, cloth, carpet, wood, and cork. Where the surface layer
is amenable to
being pressed through rollers, the surface layer can be pressed onto a hot
plastic composite
substrate using rollers. Wood surface layers might be thin enough and pliable
enough, such as
around 2 mm, to pass through the rollers. In the case of surface layers that
are not amenable to
an extrusion process, such as ceramic, tile, glass, etc., those surface layers
might be applied
just after the substrate has exited a last roller, but while the substrate is
still hot enough to
adhere to the surface layer. In any case, the flooring can be manufactured in
a continuous
process rather than having to be cut into slabs for further processing.
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[0029] For some surface layers, it may use a material that is not waterproof,
such as cork,
paper, wood, etc., but these are typically decorative veneer. As such, there
is less of a
concern with expansion and contraction, as the plastic core is rigid enough
that temperature
and moisture changes would not significantly affect warping and the like. The
surface layer
can have a protective face layer to add wear resistance or stain resistance,
with the core
providing the rigidity and stability of the plank.
[0030] The substrate (comprising a plastic composite core and possibly also a
plastic
composite base material layer) may be extruded from a mixture of one or more
of polyvinyl
chloride (PVC) powder, coarse whiting and light calcium compound powder,
stabilizer,
polyethylene (PE) wax, internal lubricant, plasticizer, and impact modifier.
For example, the
substrate may be made using PVC powder, course whiting and light calcium
powder, and
stabilizer. The substrate may also be made without using light calcium powder.
The
materials of the substrate may be blended together, and then extruded. In some
aspects, the
substrate may be blended and extruded into two or more layers of plastic
substrate. The
plastic composite base material layer might be a layer on the floor-facing
side of an HDPC
substrate that adds slip resistance and gives enhanced sound properties. Some
substrates
might be made with no plasticizer component.
[0031] One method of producing an engineered plank as described herein
includes the
following steps:
[0032] Step 1: Mix PVC powder with coarse whiting and light calcium compound
powder,
stabilizer, PE wax, internal lubricant, plasticizer, and impact modifier by
proportion of
weight. Each of these components may be added in different quantities, or may
be excluded
as desired. This mixture may then be stirred. In some aspects, during the hot
mixing process,
the mixture temperature may be controlled to be approximately 110-120 C. For
example, it
may be desired to keep the mixture within 5, 10, 15, or 20 C from 115 C during
this hot
mixing process. Some subset of these components might be mixed in a cold
mixing process
prior to being mixed with the other components in the hot mixing process.
[0033] Step 2: Once the materials of the mixture are blended together, the
mixture may then
be extruded. The extruded product may be a compound which then forms the
substrate. The
product may be extruded using a number of different methods, such as using a
three-roll
calender.
[0034] Step 3: A surface layer may then be pressed and fused onto the extruded
plastic
composite base material of the substrate. For example, this may be done using
a three-roll
calender to bond the surface layer and the substrate together. In some
aspects, each roll of
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the calender may be kept at a specific temperature. For example, the first
roll of the calender
may be kept at 130 C, or between 120 and 140 C, while the second roll is kept
at 120 C, or
between 110 C and 130 C, and the third roll of the calender may be kept at 110
C, or
between 100 C and 120 C. It should be understood that a calender with less
than or more
than three rolls might also be used for this step, or other machines to bond
the two layers
together may also be used. In some aspects, controlled temperatures may be
used when
bonding the surface layer. For example, the temperature may be maintained to
be between
150 C and 200 C.
[0035] In some aspects, the surface layer may also be tiled onto the substrate
material.
Different scenarios may dictate different methods of applying a surface layer
to substrate or
base layers, depending on the materials used in the surface and other layers,
as well as
depending on the demands of a particular use for the resulting plank material.
Instead of
using glue, the surface layer is pressed to the core when the core is hot and
that can result in
the use of less volatile organic compounds (VOC' s), reduce glue-based
delamination
concerns, reduce adhesive breakdown concerns, and speed production as it
eliminates an
extra step of gluing layers together.
[0036] Step 4: After this, the plank may be cooled, sized, and cut into the
desired dimensions,
based on the needs of the particular project or the plank design.
[0037] As described above, this engineered plank does not require the use of
wood powder,
which saves natural wood material. Thermal compression and bonding the surface
layer and
substrate using the temperature from the extrusion process can avoid the
production of
formaldehyde during production, by not using glue to press and paste the
layers together.
Further, it may be much easier to continuously produce the engineered planks
described
herein than it is to produce planks that include a glue coating process. This
may make
automated production possible, which may improve production efficiency, as
well as enhance
the stability of the adhesion between the layers of the engineered plank.
[0038] FIG. 1 illustrates an exemplary engineered flooring plank 100 according
to some
aspects of the present disclosure. As illustrated, engineered flooring plank
100 includes a
surface layer 101 and a substrate 102. Surface layer 101 and substrate 102 are
thermally
compressed together. As described above, this technique avoids the use of glue
and does not
produce formaldehyde. Using a thermal compression process to securely attach
or fuse surface
layer 101 and substrate 102 together may also lead to production advantages
over other
techniques, such as allowing continuous production by reducing the glue
coating process.
Accordingly, engineered flooring plank 100 may be produced using more
automated
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production, improving production efficiency and enhancing the stability of
composite plate
adhesion between surface layer 101 and substrate 102. The continuous
production allows for
the extrusion to be continuous so that the resulting plank material can be
emitted from the
rollers or other extrusion mechanism without requiring that it be cut into
slabs for gluing.
[0039] Surface layer 101 may be made from materials such as ceramic, tile,
glass, rubber
plastic, paper, leather, metal materials, stone, cloth, carpet, cork and wood.
Other materials
may also be used, as desired. Patterned paper, not shown, may be added on top
of surface layer
101 to create a desired appearance for the finished product. Instead of
patterned paper with a
pattern printed thereon, the desired appearance might be by a printed pattern
printed on other
than paper, but used in a similar manner. Direct printing on the substrate,
such as with an inkjet
printer, might be used as well instead of paper. Where needed, a wear layer,
such as a PVC
wear layer, can be applied over the surface layer, to protect against
scuffing, scratching and
wear through.
[0040] Substrate 102 is extruded out, and may be made from a mixture including
one or more
of PVC powder, coarse whiting and light calcium compound powder, stabilizer,
PE wax,
internal lubricant, plasticizer, and impact modifier. Substrate 102 may be a
uniform mixture of
two or more of the above components, such that it has a single texture,
appearance, and
physical properties. Some components might be omitted, such as the light
calcium compound
powder.
[0041] As described above, engineered flooring plank 100 may be produced by
first mixing
a number of components of substrate 102, such as PVC powder, coarse whiting
and light
calcium compound powder, stabilizer, PE wax, internal lubricant, plasticizer,
and impact
modifier by proportion of weight. This mixture may then be stirred in order to
achieve an
even consistency. In some aspects, the formula used for the surface layer may
vary based
upon the hardness and resistance to impact needs of a particular plank. Other
technical
requirements may also dictate the composition of surface layer 101. For
example, the impact
requirements of a project might dictate that surface layer 101 be made of
materials that will
provide a cushioning feature, such that the resulting flooring made from the
planks might
more easily absorb pressure from a person walking on the floor.
[0042] The mixture used to construct surface layer 101 includes both hot
mixing and cold
mixing. During hot mixing the temperature may be controlled to be between 110-
120 C.
The mixture may be fully mixed and stirred at this temperature. The mixture
may then be
cooled to 40-45 C and continued to be stirred. After this, the mixture may be
extruded
through the extruder, which is a compound of plastic composite base material,
like substrate
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102. After this, surface layer 101 may be tiled onto the extruded substrate
102 in a fixed
position. This may be done using a three-roll calender to bond surface layer
101 and
substrate 102 together. The material of substrate 102 is formed in a single
step, which allows
continuous automated production. The temperature of bonding surface layer 101
from the
plastic composite material extrusion and the material of substrate 102 is
controlled at around
150-200 C. The press roller of a multiple roll calender can be used to design
a concave
and/or a convex mold, which may be used to form various types of designs on
surface layer
101. These molds may be used to improve the aesthetics of surface layer 101,
to increase
friction on surface layer 101, or for other purposes. After this, the layers
may be bonded, and
engineered flooring plank 100 may be cooled, sized into the desired size, and
then cut into
shape.
[0043] FIG. 2 illustrates an exemplary plank 200 according to some aspects of
the present
disclosure, using a two-layer substrate. In plank 200, a surface layer 201 is
thermally
compressed together with the substrate. The surface layer 201 may be made from
a large
variety of different materials, depending on the needs of a particular
project, a desired
appearance, and desired surface layer characteristics. For example, the
surface layer 201
maybe constructed using one or more of ceramic, tile, glass, rubber, plastic,
paper, leather,
metal materials, stone, cloth, carpet, wood, and cork.
[0044] Here, the substrate includes a first plastic composite substrate layer
221 and a
second plastic composite substrate layer 222. The substrate is extruded with
first plastic
composite substrate layer 221 and second plastic composite substrate layer
222.
[0045] The two plastic composite substrate layers 221, 222 are both blended
and extruded
from the mixture containing PVC powder, coarse whiting and light calcium
compound
powder, stabilizer, PE wax, internal lubricant, plasticizer, and impact
modifier. In some
aspects, it may be advantageous to use two or more layers of plastic composite
substrates, in
order to allow the two layers to have different physical properties. These
various materials
may be blended together into a mixture or compound, and that mixture may be
extruded
using various tools, such as a three-roll calender.
[0046] For example, first plastic composite substrate layer 221 of plastic
composite substrate
may have higher requirements on hardness and resistance to impact. This
requirement may be
met by constructing the layer from a slightly different mixture, such as
increasing a ratio of
coarse whiting in the plastic composite base material formula and decreasing a
ratio of PVC
powder and light calcium. Second plastic composite substrate layer 222 of
plastic composite
substrate may have lower requirements on hardness and resistance to impact
than first plastic
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composite substrate layer 221. In second plastic composite substrate layer
222, the mixture may
have an increased ratio of PVC powder and light calcium, and a decreased ratio
of coarse
whiting in the plastic composite base material formula. Second plastic
composite substrate layer
222 may also add a foaming agent.
[0047] First plastic composite substrate layer 221 and second plastic
composite substrate
layer 222 may be produced using a double inlet to send different plastic
composite base
material mixtures into an extruder. The compounded two-layered structure,
plastic composite
substrate layers 221, 222 may be extruded by an extruder with the same
extrusion mold. The
two plastic composite substrate layers 221, 222 may be thermally compressed
and fused with
surface layer 201 without the use of adhesives, and instead using pressure and
temperature to
fuse the layers together. The composite material of the two plastic composite
substrate layers
221, 222 may be formed in a single step, which may allow for continuous
automated
production. Where second plastic composite substrate layer 222 uses a foam
structure, with an
added foaming agent, second plastic composite substrate layer 222 may use
fewer raw
materials in production, which may result in a more economical production
cost.
[0048] As shown in FIG. 2, a plank may have multiple layers below the surface
layer. Each
of these layers may be constructed using different materials, and may have
different
purposes. For example, one or more substrate layers may be used as a wear
layer. Such a
layer may use HDPC core technology, and may be created from powder just before
the time
that the layers are fused together. Accordingly, the wear layer may still be
hot just after its
formation, and may be fused with other layers while the wear layer is still
hot. A wear layer
over a surface layer provides protection against physical abuse, such as where
the surface
layer cannot directly sustain against walking, furniture, etc. Different wear
layers add
different levels of protection.
[0049] The layer below the surface and substrate of a plank is sometimes
referred to as the
backer layer, which can be an anti-slip backing layer, in some cases. This
backer layer may
be placed on the other side of the substrate from the surface layer, such that
the anti-slip
backing layer would be in direct contact with the floor under the plank when
installed. The
anti-slip backing layer may be constructed from a softened extruded PVC layer.
One function
of the backing layer is to enhance sound properties (sound transmission and
reflective sound)
as well as anti-slip properties to ensure that the plank remains stable and
attached to the floor
underneath it while in use.
[0050] FIG. 3 illustrates an exemplary plank 300 according to some aspects of
the present
disclosure, using a three-layer substrate. In this plank 300, a surface layer
301 and the layers
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of the substrate 321, 322, 323 are attached to one another using thermal
compression. The
substrate may be extruded and compounded by three layers of plastic composite
substrates
321, 322, 323. The three layers of plastic composite substrates 321, 322, 323
may be extruded
and compounded by a mixture containing one or more of PVC powder, coarse
whiting and
light calcium compound powder, stabilizer, PE wax, internal lubricant,
plasticizer, and impact
modifier.
[0051] The different layers of the substrate 321, 322, 323 may have different
compositions, in
order to allow plank 300 to have desirable characteristics and physical
properties. For example,
second layer 322 may have lower requirements on hardness and resistance to
impact. This may
allow the use of an increased ratio of PVC powder and light calcium, and a
decreased ratio of
coarse whiting. A foaming agent may also be used in second layer 322, which
may allow for
less material to be in second layer 322, which may reduce production costs.
First layer 321 and
third layer 323 may have higher requirements with regards to hardness and
resistance to impacts,
and so these layers 321, 323 may be constructed using a higher ratio of coarse
whiting in the
plastic composite base material formula and a lower ratio of PVC powder and
light calcium.
First layer 321 and third layer 323 can be made of the identical material or
could be made of
different materials.
[0052] The three-layer 321, 322, 323 substrate may be produced in a number of
manners.
One technique for producing such a substrate includes using triple inlets to
send different
plastic composite base material mixtures into the extruder. This three-layer
321, 322, 323
substrate may be extruded using an extruder with the same mold as other
substrates, and is
then thermally compressed with surface layer 301, as described above. The
substrate is
formed in a single process, allowing for continuous production in an automated
manner.
[0053] Plank 300 may have advantages over plank 200, due to having an
additional layer.
For example, plank 300 may be harder and more resistant to impact than plank
200. For
example, one plank produced using the structure of plank 300 was found to have
a static
bending intensity of 32 MPa, and elastic modulus of 1780 MPa, an impact
strength of 160
kJ/m2, and a contraction deformation rate of 0.25%. In a 4-hour "dipping
detachment" test,
where a sample of the plank is placed in 63 C water for four hours and then
placed ice at -
20 C for four hours, and showed no signs of stratification. Further, this
plank had a
formaldehyde content of 0 PPM in testing.
[0054] The flooring plank described herein provides significant improvement in
dimensional stability over a range of temperatures, including minimal thermal
expansion and
contraction and minimal residual shape distortion after being subjected to
temperature
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transient. An exemplary flooring plank will now be explained in connection
with the
following examples. The exemplary flooring plank was formed from a mixture of:
(i)
polyvinyl chloride (PVC) powder of about 19 % to about 21 % by weight, (ii)
reclaimed
plank material of about 14% to about 18% by weight, (iii) coarse calcium
carbonate of about
56 % to about 62 % by weight, (iv) a stabilizer of about 1.9 % to about 2.5 %
by weight, (v)
an external lubricant of about 0.12% to about 0.15 % by weight, (vi) an
internal lubricant of
about 0.15% to about 0.30% by weight, (vii) a plasticizer of about 0.12% to
about 0.15% by
weight, and (viii) impact modifier of about 2.0% to about 2.5%. The cold mix
temperature
was between 40 C and 45 C. The hot mix temperature was between 130 C-135 C.
[0055] The mixture was then extruded using a three roll calender, where the
rolls were
maintained at a temperature of between 165 C ¨ 180 C. The surface layer and
wear layer
were pressed and fused onto extruded plank at a temperature of 150 to 200 .
The density of
the resultant plank was about 1.995 tonne/m3.
[0056] Commercially available flooring products were obtained and tested in
comparison to
the exemplary flooring plank described above, "Test piece 1". The comparable
flooring
products were: (i) Test piece 2: Allure TM Isocore TM provided by Tower IPCO
Company Ltd,
of Dublin, Ireland; (ii) Test piece 3: Mohawk TM Solid TechTm provided by
Mohawk
Industries, Inc. of Calhoun, Georgia; and (iii) Test piece 4: ArmstongTm Luxe
PlankTm
provided by Armstrong Hardwood Flooring Company of Lancaster, Pennsylvania.
For
Examples 1-2 below, the nominal test specimen size was about 140 mm x 140 mm,
and the
nominal test sample thickness varied depending upon the test piece. Test piece
1 had a
thickness of about 5.42 mm. Test piece 2 (Allure Th4 Isocore Tm) had a
thickness of about
6.15 mm. Test piece 3 (Mohawk TM Solid TechTm) had a thickness of about 5.70
mm. Test
piece 4 (ArmstongTm Luxe Plank had a thickness of about 6.74 mm.
[0057] Example 1: The test pieces were compared for dimensional changes at
lower
temperatures. The test pieces were first conditioned at a laboratory
environment at a
temperature of about 60 F and relative humidity of 50% for 24 hours. The test
pieces were
then measured and the measurements recorded. The test pieces were then
subjected to a
second, depressed temperature environment in a freezer in an air environment
at a
temperature of about -5 F for 24 hours. The temperature was verified using a
hanging
freezer thermometer and a generic laser thermometer. The test specimens were
removed
from the second environment, and then immediately re-measured. The dimensional
differences are shown below.
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Test Specimen Test Mode L:1 W:1 L:2 W:2 Decrease
Change (%)
Test Piece 1 Conditioned 140.46 140.43 140.55
140.23 N/A
- 5 F 140.37 140.35 140.43 140.17
.032%
Test Piece 2
Allure TM Conditioned 140.46 140.50 140.54
140.1 N/A
Isocore TM - 5 F 140.29 140.35 140.37
140.29 .107%
Test Piece 3
Mohawk IM Conditioned 140.49 140.41 140.46 140.30
N/A
SolidTech TM - 5 F 140.34 140.28 140.32
140.20 .093%
Test Piece 4
Armstrong TM Conditioned 140.38 140.37 140.47
140.28 N/A
Luxe Planklm - 5 F 140.11 140.13 140.23
140.11 .164%
As shown above, Test Piece 1 exhibited the lowest percentage change in
dimension after
being subjected to the first laboratory environment and then the second
lowered temperature
environment.
[0058] Example 2: The test pieces were compared for resistance to extreme
elevated
temperatures. Specimens were first conditioned at the laboratory environment
of a
temperature of about 60 F and relative humidity of 50% for 24 hours. The test
pieces were
then measured and the measurements recorded. The test pieces were then
subjected to an
extreme elevated temperature environment in a test oven. The test oven was
first preheated
to a temperature of about 200 F in an air environment. The samples were then
placed in the
test oven at about 200 F for one hour. The temperature was verified using a
generic laser
thermometer on internal surfaces of the oven. The test specimens were then
removed from
the second environment, and then immediately re-measured. The dimensional
differences are
shown below.
Test Specimen Test Mode L:1 W:1 L:2 W:2 Decrease
Change
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(A)
Test Piece 1 Conditioned 140.02 140.00 139.92 140.15 N/A
200 F 139.85 140.05 139.73 140.20 -.045%
Test Piece 2
Allure TM Conditioned 140.52 140.45 140.41 140.53
N/A
Isocore TM 200 F 141.05 * 140.99 * .395%
Test Piece 3
MohawkTM Conditioned 140.24 140.33 140.35 140.21 N/A
SolidTechTM 200 F 140.70 140.67 140.81 140.66 .305%
Test Piece 4
ArmstrongTm Conditioned 139.52 139.43 139.43 139.46 N/A
Luxe Plank 200 F 140.16 * 140.45 * .595%
*not measured because of distortion
As shown above, Test Piece 1 exhibited the lowest percentage change in
dimension after
being subjected to the first laboratory environment and then the second
elevated temperature
environment.
[0059] In addition, Test Piece 1 exhibited very low deviation from flatness
after being
subjected to the first laboratory environment and then the second elevated 200
F temperature
environment. A chart of the flatness results is shown below.
Test Specimen Shape X Dir. X Dir. X Dir. Y Dir. Y Dir.
Y Dir.
Max. Max. Diff. Max. Max. Diff.
Dev. Dev. Dev. Dev.
Test Piece 1 Flat .2134 .2288 .015 .2081 .2135 .005
Test Piece 2
AllureTm Convex .7376 .7978 .060 .2209 .7378 .517
Isocore TM
Test Piece 3
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MohawkTM Concave .2131 .2647 .052 .2154 .2660 .051
SolidTech TM
Test Piece 4
ArmstrongTM Convex .5806 .5986 .018 .2624 .5777 .315
Luxe
PlankTM
In particular, as to Test Piece 1, at least one of top and bottom surfaces of
the plank had an
unweighted maximum surface flatness deviation of no greater than .015 over the
140 mm top
surface of the sample or about .003 inches per inch of surface. As to Test
Piece 2, the
unweighted maximum surface flatness deviation was about .517 inches over the
140 mm top
surface of the sample or about .094 inches per inch of top surface. As to Test
Piece 3, the
unweighted maximum surface flatness deviation was about .052 inches over the
140 mm top
surface of the sample or about .009 inches per inch of top surface. As to Test
Piece 4, the
unweighted maximum surface flatness deviation was about .315 inches over the
140 mm top
surface of the sample or about .057 inches per inch of top surface.
[0060] Figures 8-11 show diagrams of flatness for each sample in a
topographical format.
Figures 12-15 show cross sectional diagrams of the flatness for each sample.
The flatness
was measured with the test sample un-fixtured (i.e., freestanding) relative to
the reference
surface and without weight applied.
[0061] Example 3: Tensile test - A test sample of each material was formed in
a 40 mm x
40 mm blank. The thickness of each test sample was dependent upon the material
tested.
Test piece 1 had a thickness of about 5.42 mm. Test piece 2 (Allure TM Isocore
Tm) had a
thickness of about 6.15 mm. Test piece 3 (Mohawk Th4 Solid Tech) had a
thickness of
about 5.70 mm. Test piece 4 (Armstone Luxe Plank Tm had a thickness of about
6.74 mm.
The test samples were conditioned in a laboratory environment at a temperature
of about 68
F and a relative humidity of 52% for 24 hours. The specimens were subjected to
a force
applied to the top surface with the bottom surface fixed in the test stand.
The force at which
each sample yielded is shown in the chart below along with a corresponding
tensile strength.
Test Specimen Yield Tensile Force
Yield Tensile Strength
(lbs) (psi)
Test Piece 1 1075 433.5
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Test Piece 2
Allure TM 125 50.4
Isocore TM
Test Piece 3
Mohawk IM 1025 413.3
SolidTech TM
Test Piece 4
Armstrong 225 90.7
Luxe PlankTm
Test Piece 1 exhibited the highest yield strength.
[0062] Example 5: The density of the test pieces is shown below.
Test Specimen Density
1.995 tonne/m3
Test Piece 1
Test Piece 2 1.335 tonne/m3
Allure TM
Isocore TM
Test Piece 3 1.324 tonne/m3
MohawkIM
SolidTech TM
Test Piece 4 1.105 tonne/m3
Armstrong
Luxe PlankTm
As shown above, Test Piece 1 had the highest density.
[0063] In other variations, the surface layer might have a thicker wear layer
that would sit
over the HDPC core substrate and the HDPC core substrate would have a softer
PVC backing
to provide for comfort and anti-slip. In such cases, the thicker wear layer
can be part of the
surface layer or the substrate. Typically, the wear layer can be part of the
surface layer. A
wear layer might be clear, covering a decorative veneer surface layer and
simultaneously
fused together on the HDPC core substrate.
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[0064] In this manner, multiple layers can be fused and those layers might
include a surface
layer, a wear layer (which might be HDPC and created from powder just before
the time of the
fusing), and an anti-slip backing layer (if used). This bonding process is
done by fusing the
layers all together while the wear layer is hot just after extrusion or during
extrusion.
[0065] FIG. 4 is a diagram illustrating a process for embossing in
registration (EIR) as part of
an extrusion process. As a result of the EIR process, the planks will have an
embossed pattern
rather than being flat on the exposed surface of the plank. The embossed
pattern preferably
corresponds to the visual pattern of a paper layer that is part of the surface
layer.
[0066] While unregistered embossing might be used, such as where there is no
particular
visual pattern in the surface layer but a completely smooth wear layer is not
desired, a pattern
could be embossed onto the planks at an arbitrary position. In preferred
embodiments, the
texture that is applied aligns with a print pattern of the surface layer. In
some cases, the
texture preferably aligns to the print pattern within a strict tolerance of
less than 1 mm.
[0067] In order to ensure that the embossed pattern aligns with the visual
pattern, the speed
of the roller that does the embossing is variably controlled based on sensors
that detect the
rate that the substrate is created, possibly by monitoring the rate of uptake
of the surface
layer. In this manner, the surface layer is embossed in registration with the
visual pattern of
the surface layer. Alternatively, the rotation rate of the embossing roller is
varied to match the
pressure being applied by the vinyl material, which also can correspond to the
rate at which
the extrusion is occurring.
[0068] As shown in FIG. 4, a roller 402 provides the embossing when materials
are
extruded between roller 402 and another roller 404. Although not shown, roller
404 might
provide an anti-slip embossing on the lower side of the plank which also gives
better sound
characteristics, but that does not necessarily require any particular
alignment. Rollers 402 and
404 would cause a surface layer 406 to be bonded to a substrate 408 at some
high
temperature, while also embossing surface layer 406. The embossing is provided
by a raised
or carved pattern on roller 402 formed by structures 409. Structures 410
behind structures
409 illustrate that the pattern can go across roller 402. A motor (not shown)
controlling the
rotation of roller 402 would preferably be timed with the uptake of surface
layer 406 so that
structures 409, 410 correspond to visual patterns on a printed paper portion
of surface layer
406.
[0069] Conventional methods might use manual visual alignment to align a
separate plate
above a paper layer having a pattern thereon and aligning marks from the
textured plate with
marks on the paper. This can be difficult, slow, and time consuming and
involve considerable
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waste where the alignment is off by human error or otherwise. With the
approach here, the
process is fast and accurate and needs minimal manual intervention and limits
waste.
[0070] FIG. 5 is a schematic diagram of a production system for manufacturing
the
engineered planks. As illustrated there, materials are mixed at the right and
heated to various
extents, including a hot mix and a cold mix. The substrate materials can then
be output by a
panel mould to a set of rollers 502.
[0071] FIGs. 6A and 6B illustrate elements of FIG. 5 in expanded views.
[0072] FIG. 7 shows the rollers of FIG. 5 in greater detail. As shown there,
there are three
rollers that are maintained at particular temperatures (130 C, 120 C, and 110
C,
respectively). Between the second and third rollers, the surface layer is
pressed into the
substrate. The embossing might be done at the second roller. The surface layer
in this
example comprises a wear layer 602 and a color printed paper layer 604. Note
that these both
go into the roller system, between the first and second rollers, along with
the substrate. They
then continue between the second and third rollers accordingly.
[0073] Further embodiments can be envisioned to one of ordinary skill in the
art after reading
this disclosure. In other embodiments, combinations or sub-combinations of the
above
disclosed invention can be advantageously made. The example arrangements of
components
are shown for purposes of illustration and it should be understood that
combinations, additions,
re-arrangements, and the like are contemplated in alternative embodiments of
the present
invention. Thus, while the invention has been described with respect to
exemplary
embodiments, one skilled in the art will recognize that numerous modifications
are possible.
[0074] The specification and drawings are to be regarded in an illustrative
rather than a
restrictive sense. It will, however, be evident that various modifications and
changes may be
made thereunto without departing from the broader spirit and scope of the
invention as set forth
in the claims and that the invention is intended to cover all modifications
and equivalents
within the scope of the following claims.
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