U.S. patent application number 14/536029 was filed with the patent office on 2015-03-05 for core, panel blank, floor panel and methods of their production.
The applicant listed for this patent is AB Gustaf Kahr. Invention is credited to Peter Gustafsson, Dan Sigfridsson.
Application Number | 20150064390 14/536029 |
Document ID | / |
Family ID | 46027985 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150064390 |
Kind Code |
A1 |
Gustafsson; Peter ; et
al. |
March 5, 2015 |
CORE, PANEL BLANK, FLOOR PANEL AND METHODS OF THEIR PRODUCTION
Abstract
A core for inclusion in a building panel. The core presents a
pair of substantially parallel major surfaces, and comprises a
plurality of first material blocks, extending between said major
surfaces and arranged with their respective principal directions
substantially parallel with said major surfaces and extend
90.degree..+-.45.degree. to a principal direction of the core; and
a plurality of second material blocks, extending between said major
surfaces and being arranged alternatingly with said first material
blocks along the principal direction of the core. The first
material blocks and said second material blocks differ
substantially with respect to at least one material property.
Inventors: |
Gustafsson; Peter; (Molle,
SE) ; Sigfridsson; Dan; (Hovmantorp, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AB Gustaf Kahr |
Nybro |
|
SE |
|
|
Family ID: |
46027985 |
Appl. No.: |
14/536029 |
Filed: |
November 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2012/058443 |
May 8, 2012 |
|
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14536029 |
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Current U.S.
Class: |
428/77 ;
29/897.32; 428/106; 428/192; 428/195.1 |
Current CPC
Class: |
E04C 2/10 20130101; E04C
2/246 20130101; Y10T 428/24802 20150115; Y10T 428/24066 20150115;
Y10T 29/49629 20150115; E04F 15/166 20130101; E04C 2/34 20130101;
E04F 15/02038 20130101; E04C 2/205 20130101; E04F 15/041 20130101;
E04C 2/38 20130101; Y10T 428/24777 20150115 |
Class at
Publication: |
428/77 ;
428/195.1; 428/192; 428/106; 29/897.32 |
International
Class: |
E04F 15/02 20060101
E04F015/02; E04C 2/24 20060101 E04C002/24; E04C 2/38 20060101
E04C002/38; E04C 2/34 20060101 E04C002/34; E04C 2/20 20060101
E04C002/20; E04C 2/10 20060101 E04C002/10 |
Claims
1. A floor panel, comprising: a decorative layer, and a core layer
arranged below the decorative layer when the floor panel is
substantially horizontally oriented, a balancing layer, wherein the
core layer is sandwiched between the balancing layer and the
decorative layer, wherein the core layer comprises a plurality of
wood blocks arranged with their respective principal fiber
directions substantially parallel with a plane defined by a major
surface of the floor panel and substantially perpendicular to a
principal direction of the floor panel, wherein the core layer
comprises a plurality of second material blocks, made from a
different material than said wood blocks, and wherein along the
principal direction of the floor panel, the core layer presents
alternating portions formed of said wood blocks and of said second
material blocks, wherein the second material blocks have lower
density than said wood blocks and/or lower tensile strength in a
direction parallel to said principal fiber directions than said
wood blocks, wherein the wood blocks comprise wood blocks of a wood
quality, which is lower than or equal to at least one of the
standards identified as V according to the Swedish "Grona boken"
("The Green book") standard of 1960, B according to the Swedish
"Bl{dot over (a)}a boken" ("The Blue book") standard of 1994, or
G4-2/G2-2 of the European EN 1611-1 standard of 2000.
2. The floor panel as claimed in claim 1, wherein along the
principal direction of the floor panel, a total length of the
second material blocks is less than a total length of the wood
blocks.
3. The floor panel as claimed in claim 1, wherein along the
principal direction of the floor panel, a total length of the
expanded second material blocks is more than 5%, preferably more
than 10%, 20%, 30% or 40% of a total length of the floor panel.
4. The floor panel as claimed in claim 1, wherein the second
material blocks comprises expanded polymer material blocks, such as
at least one of expanded polyethylene, expanded polypropylene and
expanded polystyrene extruded polystyrene foam.
5. The floor panel as claimed in claim 1, wherein the second
material blocks comprise an engineered wood product.
6. The floor panel as claimed in claim 1, wherein the second
material blocks comprise a non-expanded polymer material comprising
filler material.
7. The floor panel as claimed in claim 1, wherein the core layer
further comprises a reinforcing inset portion.
8. The floor panel as claimed in claim 1, wherein the second
material blocks are provided with surface coating at an edge
portion where said second material blocks are exposed.
9. The floor panel as claimed in claim 1, wherein the second
material blocks present a portion of increased density at an edge
portion where said second material blocks are exposed.
10. The floor panel as claimed in claim 1, wherein the decorative
layer comprises wood.
11. The floor panel as claimed in claim 1 wherein the wood blocks
comprise wood blocks of a wood quality, which is lower than or
equal to at least one of the standards identified as VI according
to the Swedish "Grona boken" ("The Green book") standard of 1960, C
according to the Swedish "Bl{dot over (a)}a boken" ("The Blue
book") standard of 1994, or G4-3/G2-3 of the European EN 1611-1
standard of 2000.
12. The floor panel as claimed in claim 1 wherein the wood blocks
comprise wood blocks of a wood quality, which is lower than or
equal to at least one of the standards identified as VII according
to the Swedish "Grona boken" ("The Green book") standard of 1960, D
according to the Swedish "Bl{dot over (a)}a boken" ("The Blue
book") standard of 1994, or G4-4/G2-4 of the European EN 1611-1
standard of 2000.
13. A method of making a floor panel, comprising: arranging a
plurality of elongate wood blocks side by side in a co-planar
manner, with their respective longitudinal directions substantially
parallel with each other to form a core layer, providing the core
layer with at least a decorative layer to form a panel blank,
providing the core layer with a balancing layer, such that the core
layer is sandwiched between the balancing layer and the decorative
layer, cutting the panel blank to form an elongate floor panel
blank, such that the longitudinal directions of the wood blocks are
substantially perpendicular to a principal direction of the floor
panel blank, providing a plurality of second material blocks
arranged alternatingly with the wood blocks along the principal
direction of the floor panel blank, said second material blocks
having lower density than said wood blocks and/or lower tensile
strength in a direction parallel to said principal fiber directions
than said wood blocks, the wood blocks comprising wood blocks of a
wood quality, which is lower than or equal to at least one of the
standards identified as V according to the Swedish "Grona boken"
("The Green book") standard of 1960, B according to the Swedish
"Bl{dot over (a)}a boken" ("The Blue book") standard of 1994, or
G4-2/G2-2 of the European EN 1611-1 standard of 2000.
14. The method as claimed in claim 13, further comprising forming
locking means along said principal direction of the floor panel
blank.
15. The method as claimed in claim 14, further comprising providing
a surface treatment on at least part of the mechanical connecting
means.
16. The method as claimed in claim 15, wherein the surface
treatment comprises applying a coating to an exposed part of said
second material block.
17. The method as claimed in claim 15, wherein the surface
treatment comprises thermoforming an exposed part of said second
material block.
18. The method as claimed in claim 16, wherein the surface
treatment comprises thermoforming an exposed part of said second
material block.
19. The method as claimed in claim 13 wherein the wood blocks
comprise wood blocks of a wood quality, which is lower than or
equal to at least one of the standards identified as VI according
to the Swedish "Grona boken" ("The Green book") standard of 1960, C
according to the Swedish "Bl{dot over (a)}a boken" ("The Blue
book") standard of 1994, or G4-3/G2-3 of the European EN 1611-1
standard of 2000.
20. The method as claimed in claim 13 wherein the wood blocks
comprise wood blocks of a wood quality, which is lower than or
equal to at least one of the standards identified as VII according
to the Swedish "Grona boken" ("The Green book") standard of 1960, D
according to the Swedish "Bl{dot over (a)}a boken" ("The Blue
book") standard of 1994, or G4-4/G2-4 of the European EN 1611-1
standard of 2000.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of International
Application No. PCT/EP2012/058443, filed May 8, 2012, of which
priority is claimed, the disclosure of which is hereby incorporated
by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to building panels and in
particular to floor panels.
[0003] More specifically, the present disclosure relates to a core
for inclusion in a building panel, such as a floor panel; a blank
for forming building panels and to methods for forming such a core,
blank and building panel.
BACKGROUND
[0004] It is known to provide parquet floor panels comprising a
core which is formed of a plurality of low-grade wood blocks (also
termed "slats" or "lamellae", which are arranged with their fiber
direction perpendicular to a longitudinal direction of the floor
panel. The core is sandwiched between a decorative layer, typically
of an about 3 mm wood surface layer, and a balancing layer,
typically of an about 2 mm wood veneer. The decorative layer and
the balancing layer are glued to the core.
[0005] Floor panels as described above have been manufactured since
the 1940's, and, apart from improvements in surface treatment, glue
technology and the introduction of mechanical locking systems, have
undergone relatively little change.
[0006] Examples of such parquet floor panels are disclosed in e.g.
WO96/30177 A1 and US2005/0208255A1.
[0007] It is desirable to further reduce the cost of floor panels
of the above referenced type.
Definitions
[0008] The term "panel blank" is understood as a piece of material
which has substantially the same format as the end product, but
which has not been completed with respect to the formation of e.g.
a locking system at edges of the panel blank.
[0009] The term "blank", is understood as a piece of material,
which is intended to be divided into a plurality of panel
blanks.
[0010] The "major surface" is typically the upwardly or downwardly
surface of a core, blank, panel blank or building panel or floor
panel. These surfaces are typically parallel with each other.
[0011] A "principal direction" of a core, blank, panel blank or
building panel or floor panel may be a longitudinal direction in a
case where the item is elongate (i.e. substantially rectangular and
non-square). As an alternative, or complement, the principal
direction may be a direction which is substantially parallel with a
direction along which another layer than the core layer, e.g. a
decorative layer and/or a balancing layer, forming part of the
blank, panel blank or floor panel presents its major bending
strength and/or major tensile strength, such as a principal fiber
direction of the decorative layer and/or of the balancing
layer.
[0012] A "principal fiber direction" is defined as the direction
along which most of the fibers of the wood block or veneer extend.
Typically, the principal fiber direction substantially coincides
with a longitudinal direction of the wood block since lumber is
normally sawn so as to have its fibers extend substantially
longitudinally.
[0013] An "expanded polymer material" is understood as a polymer
material which contains a resin and a substantial amount of
gas-filled inclusions.
SUMMARY
[0014] The present invention aims generally at overcoming or
alleviating some disadvantages of prior art floor panels, with a
particular focus on reduction of cost.
[0015] The invention is defined by the appended independent claims,
with embodiments being set forth in the dependent claims, in the
following description and in the drawings.
[0016] According to a first aspect, there is provided a core for
inclusion in a building panel. The core presents a pair of
substantially parallel major surfaces, and comprises a plurality of
first material blocks, extending between said major surfaces and
arranged with their respective principal directions substantially
parallel with said major surfaces and extending
90.degree..+-.45.degree. to a principal direction of the core; and
a plurality of second material blocks, extending between said major
surfaces and being arranged alternatingly with said first material
blocks along the principal direction of the core. The first
material blocks and said second material blocks differ
substantially with respect to at least one material property.
[0017] Such a core provides an opportunity for improved control of
properties associated with the core, such as strength and weight,
and of the cost of the core.
[0018] The "principal direction of the core" may be understood as a
longitudinal direction of the core, which is particularly
applicable when the core is to be produced as an elongate or
substantially continuous sheet-like product.
[0019] The first material blocks preferably extend
90.degree..+-.30.degree., 90.degree..+-.15.degree.,
90.degree..+-.5.degree. or substantially perpendicular to the
principal direction of the core. The second material blocks may
typically extend substantially parallel to the first material
blocks.
[0020] By "differ substantially" is meant that the difference is
more than what would be incurred by the mere random variation which
occurs between blocks of material which are of the same type and
orientation, such as would be the case between two pieces of the
same type of wood, or as would be the case due to manufacturing
tolerances, etc.
[0021] The core may present a thickness between its major surfaces
of about 5 mm to about 50 mm, preferably about 7 mm to about 15
mm.
[0022] A cross section of the core, taken along the principal
direction of the core, perpendicular to the major surfaces and
containing an equal number of whole first material blocks and whole
second material blocks, may present less than 50% by area of said
second material blocks.
[0023] Hence, the first material blocks may form more than 50% by
volume of the core, not counting any edge reinforcing insets.
[0024] The core may comprise at least one web, which may be
attached to and substantially cover at least one of the core's
major surfaces.
[0025] The web may comprise at least one of a non-woven material, a
woven material, a pulp-based material and a polymer film.
[0026] The web may comprise a material having adhesive properties
with respect to said first blocks and/or said second material
blocks.
[0027] The web may be flexible enough to allow the core to bend so
as to allow an angle of more than 5.degree., preferably more than
10.degree., more than 15.degree., more than 20.degree. or more than
25.degree., between major surface normals of a pair of adjacent
first material blocks.
[0028] The first material blocks and second material blocks may be
formed from materials, which differ with respect to at least one of
material type, material composition, material density, material
hardness, material tensile strength and material elastic
modulus.
[0029] With respect to "material type", the blocks may be formed of
different materials, such as wood and expanded polymer material or
different types of polymer materials or different kinds of
wood.
[0030] With respect to "material composition", the blocks may be
formed of polymer materials having different material compositions
and/or of polymer materials containing different types of fillers
or additives.
[0031] With respect to material density, the first material blocks
may have a higher density than the second material blocks.
[0032] With respect to "material hardness", the first material
blocks may be harder than the second material blocks.
[0033] With respect to "material orientation" the first material
blocks and the second material blocks may have anisotropic
properties, and may be oriented in different directions. For
example, the first material blocks may be have fibers extending
substantially perpendicular to the principal direction of the core,
while the second material blocks extend substantially parallel to
the principal direction of the core, or parallel to a thickness
direction of the core.
[0034] With respect to "material tensile strength", the first
material blocks may have higher tensile strength than the second
material blocks.
[0035] With respect to the "material elastic modulus", the first
and second materials may present different bending stiffness. Such
different bending stiffness may typically be presented at least
with respect to the longitudinal direction of the material
blocks.
[0036] The principal direction of the first material blocks may be
substantially parallel with a direction of major bending stiffness
and/or of major tensile strength of the first material blocks.
[0037] In one set of embodiments, the first material blocks may be
formed from a wood material.
[0038] The principal direction of the first material blocks may
thus be substantially parallel with a principal fiber direction of
the wood material.
[0039] The wood blocks may comprise wood blocks of a wood quality,
which is lower than or equal to V according to the Swedish "Grona
boken" ("The Green book") standard of 1960, preferably lower than
or equal to VI or lower than or equal to VII. As an alternative,
the wood blocks may be of a wood quality which is lower than or
equal to B according to the Swedish "Bl{dot over (a)}a boken" ("The
Blue book") standard of 1994, preferably lower than or equal to C
or lower than or equal to D. As yet another alternative, the wood
blocks may comprise wood blocks of a quality which is lower than or
equal to G4-2/G2-2 of the European EN 1611-1 standard of 2000,
preferably lower than or equal to G4-3/G2-3 or lower than or equal
to G4-4/G2-4. These standards are hereby incorporated by
reference.
[0040] Preferably, the wood is of quality V or VI according to the
"Grona boken" standard, or of a corresponding quality according to
any other standard.
[0041] The wood blocks may also, or as an alternative, be of a
strength class which is lower than or equal to C18 of the EN 338
standard, preferably lower than or equal to C16 or lower than or
equal to C14.
[0042] In another set of embodiments, the first material blocks may
be formed of a composite material.
[0043] The composite material may comprise a polymer material
matrix, and a filler material and/or a reinforcing material.
[0044] The filler material may comprise wood dust, wood fibers,
wood particles, wood chips, a mineral-based filler or a polymer
material.
[0045] The reinforcing material may be arranged to provide
anisotropic strength properties of the composite material.
[0046] For example, the reinforcing material may comprise elongate
fibers extending substantially parallel with the principal
direction of the first material blocks. Hence, the first material
blocks may be formed from an engineered wood material.
[0047] Non-limiting examples of engineered wood materials include
fiberboards, chip boards, particle boards, and reconstituted wood.
It is possible to form the first and second material blocks from
different types of engineered wood materials.
[0048] The second material blocks may be formed from an expanded
polymer material, an engineered wood material or a non-expanded
polymer material. Expanded polymer material blocks may comprise at
least one of expanded polyethylene, expanded polypropylene and
expanded polystyrene extruded polystyrene foam.
[0049] An expanded polymer material may be non-filled or filled
with e.g. fillers in the form of wood dust, wood fibers, wood
particles, wood chips, a mineral-based filler and/or a polymer
material.
[0050] Typically, the second material blocks would be formed of an
engineered wood material having lower cost, strength and/or density
than that of the first material blocks.
[0051] Typically, a non-expanded polymer material may comprise one
or more polymer matrix materials and fillers in the form of wood
dust, wood fibers, wood particles, wood chips, a mineral-based
filler and/or a polymer material, having lower cost and/or strength
than that of the first material blocks. The density may be lower or
higher. A low density would provide weight advantages, while a
higher density may provide desirable sound absorption or reduction
properties. According to a second aspect, there is provided a blank
for forming a building panel, comprising a core as described above,
and at least one structural layer substantially covering least one
of the core's major surfaces.
[0052] A building panel may, as non-limiting examples, be a floor
panel, a wall panel, a ceiling panel or a roof panel.
[0053] The structural layer may comprise a decorative layer and/or
a wear layer.
[0054] The structural layer may further comprise a reinforcing
layer arranged between the core and the decorative layer.
[0055] In one set of embodiments, the decorative layer may comprise
a laminate material.
[0056] In another set of embodiments, the decorative layer may
comprise wood.
[0057] In another set of embodiments, the decorative layer may
comprise (or consist essentially of) a plastic material, e.g.
including polyvinyl chloride, acrylic, epoxy, polyurethane; rubber
or rubber-like material; or linoleum.
[0058] In some embodiments, the decorative layer may be formed
essentially of a solid wood material.
[0059] The blank may further comprise a balancing layer comprising
a wood veneer, a polymer film, a woven web, a non-woven web and/or
a pulp based material.
[0060] The principal direction of the core may be substantially
parallel with a direction of major bending stiffness of at least
one of the structural layers.
[0061] The principal direction of the core may be substantially
parallel with a longitudinal direction of the blank.
[0062] According to a third aspect, there is provided a building
panel formed from a blank as disclosed above. Such floor panel may
be provided with a locking system along at least two of its
opposing edge portions.
[0063] According to a fourth aspect, there is provided a method of
making a core for a building panel, the core presenting a pair of
substantially parallel major surfaces. The method comprises
providing a plurality of first material blocks, arranging the
plurality of first material blocks with their respective principal
directions substantially parallel with the major surfaces and
substantially perpendicular to a principal direction of the core,
and providing second material blocks arranged alternatingly with
said first material blocks in said principal direction of the
core.
[0064] The step of providing said second material blocks may
comprise arranging pre-formed second material blocks alternatingly
with said first material blocks.
[0065] The step of providing said second material blocks may
comprise providing a polymer material resin in a space providing a
longitudinal separation of two of said first material blocks and
subsequently causing the polymer material resin to expand.
[0066] The step of providing the second material block may comprise
providing the second material block with a thickness which at least
initially is greater than that of said first material blocks.
[0067] The method may further comprise compressing said second
material block in connection with the application of a web or
structural layer to the core.
[0068] The method may further comprise using said second material
block to provide adhesion between the core and the layer.
[0069] According to a fifth aspect, there is provided a method of
making a building panel, the method comprising providing a blank as
described above, cutting a building panel blank from the blank
along the principal direction of the core to a format suitable for
providing a building panel, and forming mechanical connecting means
along at least one edge of the floor panel blank.
[0070] The method may further comprise providing a surface
treatment on at least part of the mechanical connecting means.
[0071] As an alternative or additional measure, the surface
treatment may comprise applying a coating to an exposed part of
said second material block.
[0072] As an alternative or additional measure, the surface
treatment may comprise thermoforming an exposed part of said second
material block.
[0073] According to a sixth aspect, there is provided a floor
panel, comprising a decorative layer and a core layer. The core is
arranged below the decorative layer when the floor panel is
substantially horizontally oriented. The core layer comprises a
plurality of wood blocks arranged with their respective principal
fiber directions substantially parallel with a plane defined by a
major surface of the floor panel and substantially perpendicular to
a principal direction of the floor panel. The core layer comprises
a plurality of second material blocks, which are made from a
different material than said wood blocks, and along the principal
direction of the floor panel, the core layer presents alternating
portions formed of said wood blocks and of said second material
blocks.
[0074] A "second material block" is understood as a block of
material which is different from the material of the wood blocks.
The second material blocks may e.g. be of generally lower quality
(strength and/or stiffness) and/or cost than the wood blocks.
Hence, the second material blocks mainly serve to fill the space
between the wood blocks, and possibly to provide sound
reduction.
[0075] A floor panel comprising a plurality of second material
blocks may be produced at reduced cost compared with a floor panel
comprising only wood blocks, since such second material may be less
costly than even the lowest quality wood.
[0076] Moreover, the second material may reduce weight of the floor
panel as compared to a floor panel comprising only wood, thus
reducing cost of transportation and facilitating installation.
[0077] Along the principal direction of the floor panel, a total
length of the second material blocks may be less than a total
length of the wood blocks.
[0078] Along the principal direction of the floor panel, a total
length of the second material blocks may be more than 5%,
preferably more than 10%, 20%, 30% or 40% of the total length of
the floor panel. Typically, the total length of the second material
blocks is less than 50% of the total length of the floor panel.
[0079] The second material blocks may have lower density than said
wood blocks and/or lower tensile strength in a direction parallel
to said principal fiber directions than said wood blocks.
[0080] The second material blocks may comprise expanded polymer
material blocks, such as at least one of expanded polyethylene,
expanded polypropylene and expanded polystyrene extruded
polystyrene foam.
[0081] As an alternative or complement, the second material blocks
may comprise an engineered wood product.
[0082] As yet another alternative or complement, the second
material blocks may comprise a non-expanded polymer material
comprising filler material.
[0083] The wood blocks may comprise, or consist essentially of,
wood blocks of a wood quality, which is lower than or equal to V
according to the Swedish "Grona boken" ("The Green book") standard
of 1960, preferably lower than or equal to VI or lower than or
equal to VII. As an alternative, the wood blocks may be of a wood
quality which is lower than or equal to B according to the Swedish
"Bl{dot over (a)}a boken" ("The Blue book") standard of 1994,
preferably lower than or equal to C or lower than or equal to D. As
yet another alternative, the wood blocks may comprise wood blocks
of a quality which is lower than or equal to G4-2/G2-2 of the
European EN 1611-1 standard of 2000, preferably lower than or equal
to G4-3/G2-3 or lower than or equal to G4-4/G2-4.
[0084] The wood blocks may also, or as an alternative, comprise, or
consist essentially of, wood blocks of a strength class, which is
lower than or equal to C18 of the EN 338 standard, preferably lower
than or equal to C16 or lower than or equal to C14.
[0085] Hence, wood blocks, which are of low or very low quality,
and hence cost, may be used to a great extent.
[0086] The core layer may further comprise a reinforcing inset
portion, which may be provided at a short side edge portion of the
floor panel.
[0087] Typically, the core layer of the floor panel may consist of
about 80-99% by volume, possibly 90-95% by volume, of alternating
wood and second material blocks. The remainder may consist of,
inter alia, inset pieces, adapted to provide specific parts of the
locking system.
[0088] The second material blocks may be provided with surface
coating at an edge portion where said second material blocks are
exposed.
[0089] Alternatively or as a complement, the second material blocks
may present a portion of increased density at an edge portion where
said second material blocks are exposed.
[0090] The decorative layer may comprise, or consist essentially
of, natural wood.
[0091] The floor panel may comprise a balancing layer, and the core
layer may be sandwiched between the balancing layer and the
decorative layer
[0092] According to a seventh aspect, there is provided a method of
making a floor panel, comprising arranging a plurality of elongate
wood blocks side by side in a co-planar manner, with their
respective longitudinal directions substantially parallel with each
other to form a core layer. The method further comprises providing
the core layer with at least a decorative layer to form a panel
blank, and cutting the panel blank to form an elongate floor panel
blank, such that the longitudinal directions of the wood blocks are
substantially perpendicular to a principal direction of the floor
panel blank. The method further comprises providing a plurality of
second material blocks arranged alternatingly with the wood blocks
along the principal direction of the floor panel blank. The second
material blocks have lower density than said wood blocks and/or
lower tensile strength in a direction parallel to said principal
fiber directions than said wood blocks.
[0093] The method may further comprise forming locking means along
said principal direction of the floor panel blank.
BRIEF DESCRIPTION OF THE DRAWINGS
[0094] FIG. 1 is a schematic exploded view of a panel blank.
[0095] FIG. 2 is a schematic perspective view of a panel blank.
[0096] FIG. 3 is a schematic perspective view of a part of a floor
panel.
[0097] FIG. 4 is a schematic top view of a floor panel.
[0098] FIG. 5 is a schematic cross sectional view of a floor
panel.
[0099] FIGS. 6a-6c schematically illustrate a method of producing a
blank or a panel blank.
[0100] FIGS. 7a-7d schematically illustrate a first alternative
method of producing a blank or a panel blank.
[0101] FIGS. 8a-8b schematically illustrate a second alternative
method of producing a blank or a panel blank.
[0102] FIGS. 9a-9c schematically illustrate a core.
[0103] FIG. 10 schematically illustrates a third alternative method
of producing a blank or a panel blank.
DESCRIPTION OF EMBODIMENTS
[0104] FIG. 1 is a schematic exploded view of a floor panel blank
1, comprising a decorative layer 13, a core layer 10, 11 and a
balancing layer 12. FIG. 2 shows a floor panel blank 1' in an
assembled state. The core layer 10, 11 is formed of wood blocks 10
and expanded polymer blocks 11, which are arranged alternatingly
along a longitudinal direction L of the floor panel blank. For
example, this longitudinal direction of the floor panel blank may
be substantially parallel with a principal fiber direction of a
wood veneer forming a visually exposed upper surface of the
decorative layer 13.
[0105] The wood blocks 10 may be substantially elongate, with their
respective principal fiber direction substantially coinciding with
a respective longitudinal direction l of the respective block 10. A
cross section of the wood blocks 10 may present a thickness Tw and
a width Ww. The width Ww may be greater than the thickness Tw.
[0106] The longitudinal direction l of the wood blocks 10 may
extend 90.degree..+-.45.degree. relative to the longitudinal
direction L of the floor panel blank. Preferably, the wood blocks
extend 90.degree..+-.30.degree., 90.degree..+-.15.degree.,
90.degree..+-.5.degree. or 90.degree..+-.1.degree. relative to the
longitudinal direction of the panel blank.
[0107] The wood blocks may comprise blocks of any appearance, but
for cost reasons, it may be preferred that the wood blocks
comprise, or consist essentially of, (e.g. consist of at least 50%,
at least 70%, at least 90% or at least 95%) a wood quality lower
than or equal to V according to the Swedish "Grona boken" ("The
Green book") standard of 1960, preferably lower than or equal to VI
or lower than or equal to VII; lower than or equal to B according
to the Swedish "Bl{dot over (a)}a boken" ("The Blue book") standard
of 1994, preferably lower than or equal to C or lower than or equal
to D; or lower than or equal to G4-2/G2/2 of the European EN 1611-1
standard of 2000, preferably lower than or equal to G4-3/G2-3 or
lower than or equal to G4-4/G2-4.
[0108] Moreover, the wood blocks may have a strength class lower
than or equal to C18 of the EN 338 standard, preferably lower than
or equal to C16 or lower than or equal to C14.
[0109] The wood blocks may be formed of elongate wood beams, and/or
of shorter pieces of wood which have been joined together (e.g.
using finger joints, dovetail joints and/or glue).
[0110] The expanded polymer blocks 11 may be so-called "rigid
polymer foams", which may be defined as foams that have a modulus
of elasticity (E) of about 0.02-0.4 GPa, preferably of about
0.1-0.4 GPa. The density may be in the area of 20-400 kg/m3,
preferably of about 10-100 kg/m3, most preferably of about 20-50
kg/m3.
[0111] As an alternative, the expanded polymer blocks 11 may be
so-called "flexible polymer foams", which may be defined as foams
that have a modulus of elasticity (E) of about 0.0003-0.0015 GPa.
The density may be in the area of 5-200 kg/m3.
[0112] The expanded polymer blocks 11 may be so-called closed cell
expanded polymer or open cell expanded polymer.
[0113] Examples of materials include polystyrene, polyurethane,
polyolefin (e.g. polyethylene, polypropylene), thermosets
(phenolic, melamine, urea or combinations thereof) and polyvinyl
chloride (PVC).
[0114] The expanded polymer material blocks may comprise additives,
such as wood chips, wood particles, wood dust (saw dust, wood
flour) or wood fibers; mineral fillers (calcium, dolomite, etc);
polymeric fillers (e.g. recycled polymers, rubbers or rubber-like
materials). The expanded polymer blocks 11 are illustrated as being
substantially elongate, with their respective longitudinal
direction parallel with the longitudinal directions l of the wood
blocks 10. A cross section of the expanded polymer blocks 11 may
present a thickness Tp and a width Wp. The width Wp may be greater
than the thickness Tp.
[0115] The thickness Tw of the wood blocks may typically be on the
order of about 5-50 mm, more commonly about 5-25 mm or about 7-15
mm, and most typically about 10 mm.
[0116] Typically, the thickness Tw of the wood blocks 10 may be
substantially the same, or exactly the same, as the thickness Tp of
the expanded polymer blocks 11.
[0117] The width Ww of the wood blocks 10 may be greater than the
width Wp of the expanded polymer blocks 11. As non-limiting
examples, the width Wp of the expanded polymer blocks 11 may be
less than about 90%, less than about 80%, less than about 70% or
less than about 60% of the width Ww of the wood blocks 10.
[0118] The floor panel 1'' may thus have a core formed of
alternating wood and expanded polymer blocks along substantially
its entire length, optionally with the exception of one or both
short side edges, which may be provided with a reinforcing inset,
which may be formed of wood of a higher quality than that of the
wood blocks 10, a different type of wood, and/or of wood having a
different fiber direction, e.g. perpendicular to, that of the wood
blocks 10. Alternatively, the insets may be formed of another
material, such as MDF, HDF, polymer or polymer composite (e.g.
fiber reinforced polymer). Each of the insets may extend over less
than 15% of the floor panel's 1'' length, preferably less than 10%,
less than 5% or less than 3% of the floor panel's 1'' length.
[0119] Such insets may, additionally, or as a complement, be
provided for one or both long side edges, in which case the insets
would extend along all or part of the long side edge(s), and
perpendicular to the principal direction of the floor panel.
[0120] Referring to FIGS. 3 and 4, the floor panel 1'' may be
provided with a locking system 30, 31, 32, 33 adapted for
interconnection of the floor panel 1'' with similar or identical
floor panels. Such a locking system may be arranged to provide
mechanical or form-fit locking horizontally and/or vertically, i.e.
the floor panels may be locked together wholly or partially without
the use of glue.
[0121] In one embodiment, the long side locking system 30, 31 may
be identical with the short side locking system 32, 33. In another
embodiment, the long side locking system 30, 31 may be different
from that of the short side locking system in terms of e.g.
geometry and/or mechanical properties of the locking system.
[0122] A plurality of different systems for mechanical
interconnection of floorboards are known as such, and so are the
methods for producing them. Non-limiting examples of such systems
are shown in WO94/26999A1 U.S. Pat. No. 4,426,820, DE1211175,
DE19851200C1, FR2675174, WO99/66151, WO97/47834, JP3169967,
WO96/27721, GB1430423, WO02/55809, U.S. Pat. No. 4,819,932,
EP1863984A1 and EP1802827A1, the entire contents of which documents
are hereby incorporated herein by reference.
[0123] Hence, further description of the locking system is deemed
unnecessary.
[0124] Referring to FIGS. 6a-6c, a method of producing a floor
panel 1'' is disclosed.
[0125] Pre-cut blocks 10 of wood as well as pre-formed (e.g. cut or
moulded) blocks 11 of expanded polymer may be arranged on a first
sheet, which may be the balancing layer 12 or the decorative layer
13. The first sheet 12, 13 and/or the side of the blocks 10, 11
facing the first sheet may be provided with glue prior to the
joining of the blocks 10, 11 to the first sheet 12. Moreover, a
second sheet 13 is provided and its side facing the blocks 10, 11
and/or the side of the blocks 10, 11 facing the second sheet are
provided with glue, after which the second sheet 13 is joined with
the blocks.
[0126] The blocks 10, 11 may be arranged so as to abut each other
along their longitudinal direction l. Alternatively, a small space
in the longitudinal direction L of the floor panel may be provided
between the members of each pair of adjacent blocks. The space may
be in the order of 0.1-5 mm, preferably 1-3 mm.
[0127] After the sheets 12, 13 and blocks 10, 11 have been joined,
they may be subjected to pressure, either batchwise or
continuously, e.g. by rollers or a belt press. The pressure may be
complemented with addition of heat or other means for activating
the glue, such as ultrasound, microwaves, etc.
[0128] Typically, these steps are performed to provide a blank,
which may have a size of on the order of about e.g. 1.2 m.times.2.4
m. This blank may then be cut into floor panel blanks 1', i.e.
blanks having the general shape of the finished floor panel 1'',
but without any locking system 30, 31, 32, 33 formed along its
edges. The floor panel blanks 1' may then be subjected to milling
and optionally addition of separate elements (locking tongues,
locking elements, locking strips, etc.) to provide the desired
locking system 30, 31, 32, 33.
[0129] The decorative layer 13 may be in the form of a solid wood
sheet, which typically has a thickness of about 2-5 mm, most often
about 3 mm. The wood sheet may be composed of a single or few wood
blocks, or of a plurality of lamellae to form a block pattern on
the surface. Typically, most, or at least some, of these lamellae
are elongate and extend substantially parallel to the longitudinal
direction L of the floor panel. Alternatively, some of the lamellae
extend perpendicular to the longitudinal direction L of the floor
panel, as would be the case with floor panels for providing a
so-called Dutch floor pattern.
[0130] Alternatively, the decorative layer may be formed of a
plurality of layers, such as e.g. a reinforcement layer combined
with a thin surface layer, which is laminated or glued to the
reinforcement layer. The surface layer may be formed of e.g. a thin
(0.5-2 mm) wood veneer, or a laminate, i.e. an artificially
patterned (e.g. printed) layer, which may be laminated to, or
integrated with, a wear layer, which may comprise a polymer
material with fillers and additives for providing a hard surface.
The reinforcement layer may be formed of a plywood, MDF, HDF or
other sheet material.
[0131] A decorative layer 13 of wood or wood veneer may be natural,
i.e. uncoated, or coated/treated with e.g. lacquer, wax, oil,
varnish or any other type of surface finish, such as acrylic or
urethane based floor finishes.
[0132] The balancing layer 12 may be formed of a thin (0.5-2 mm)
sheet of wood or plywood. Alternatively, the balancing layer may be
formed of a polymer film, a woven or non-woven sheet, a pulp-based
material (such as paper) or other wood-polymer composite
material.
[0133] The floor panel typically forms part of a set of
substantially identical floor panels, which are to be joined
together to provide a flooring.
[0134] Referring to FIGS. 7a-7d, a first alternative method of
forming a blank will now be described. A first structural layer,
such as a balancing layer 12 (or a decorative layer 13) is provided
(FIG. 7a). A number of wood blocks 10 are provided and arranged on
the first structural layer. Optionally, the wood blocks 10 may be
attached (provisionally or permanently) to the structural layer.
The wood blocks 10 are arranged in a spaced manner along the
principal direction L of the blank.
[0135] A polymer resin 9 adapted for being expanded is arranged in
the spaces between the wood blocks (FIG. 7b). The polymer resin may
e.g. contain one or more expanding agents.
[0136] A second structural layer, such as a decorative layer 13 (or
balancing layer 12) is arranged so as to sandwich the wood blocks
10 between the first and second structural layers (FIG. 7c). The
second structural layer may be attached to the wood blocks
(provisionally or permanently).
[0137] The expanding agent(s) present in the polymer resin 9 is
then activated so as to expand to substantially fill up the space
between the wood blocks 10. As the polymer resin sets, hardens or
cools, the expanded polymer material blocks 11 will be
provided.
[0138] The activation of the expanding agent(s) may be achieved by
provision of heat, microwaves, ultrasound, vacuum, UV light,
etc.
[0139] The activation of the expanding agent may also cause an
activation of a glue or other attachment means for attaching the
structural layers to the wood blocks.
[0140] In a variant of this method, the wood blocks 10 may be
sandwiched between the structural layers 12, 13 prior to the
introduction of the resin 9. In this case, the resin may be
subsequently injected into the spaces formed between the wood
blocks and structural layers. In such case, the resin may, but need
not, be activated immediately on introduction, e.g. upon contact
with the surrounding atmosphere.
[0141] It is also possible to inject a non-expanding, and possibly
filled, polymer resin into the spaces formed between the wood
blocks (or other material blocks).
[0142] The resin 9 may, in addition to providing the expanded
polymer material blocks 11, also provide attachment of blocks to
the structural layers, both of the expanded polymer material blocks
and of the wood blocks. For example, the wood blocks may be
designed or arranged so as to allow for a sufficient amount of
resin to enter between the wood blocks and the structural layers,
thereby providing adhesion.
[0143] Referring to FIGS. 8a-8b, another alternative method of
producing the blank will be described.
[0144] Expanded polymer material blocks 11 are provided with a
thickness Tp which exceeds the thickness Tw of the wood blocks 10
(FIG. 8a). The blocks may be provided as pre-shaped blocks or by
activation of the expanding agent prior to application of the
second structural layer.
[0145] The second structural layer 13 may then be applied, upon
which the expanded polymer material blocks 11 are compressed (FIG.
8b). The compression may be provided in the pressing step described
with respect to FIGS. 6a-6c.
[0146] Referring to FIGS. 9a-9c, a method of producing a core
(without structural layers) will be described.
[0147] In a first embodiment (FIG. 9a), the core may be produced by
connecting alternating wood blocks 10 and expanded polymer material
blocks 11 through e.g. adhesion (surface to surface) to form a
continuous core without any structural layers.
[0148] If the expanded polymer material blocks 11 are relatively
flexible, the core may be bent and possibly even wound as a
roll.
[0149] In a second embodiment (FIG. 9b), the core may be provided
with a web 20, to which the blocks 10, 11 will be attached in to a
major surface of the core in a manner similar to what was disclosed
with respect to the first structural layer 12.
[0150] The web 20 may be a polymer film, a non-woven web, a woven
web, a pulp-based (paper or paper-like) web, a rubber film, etc.
Hence, the web may be flexible enough to allow the web to bend and
to be wound as a roll. The web may have a thickness in the area of
about 0.1-3 mm and preferably of about 0.1-1 mm.
[0151] In the third embodiment (FIG. 9c), a second web 21 may be
provided at the second face Sc1 of the core. The second web may be
identical to the first web, or it may be a different type of
material.
[0152] It is possible to form the web of a material which, e.g. on
activation will operate as a binder, adhesive or glue relative to
the core and/or to the structural layers. It is also possible to
apply a coating to, or impregnate the web with, a material which
e.g. on activation will operate as a binder, adhesive or glue
relative to the core and/or to the structural layers. In the event
that such material is tacky or pressure activated, it is possible
to provide also a protective film to one or both exposed faces of
the webs 20, 21. Such a protective film may thus be removed when
the core provided with the web is to be joined to e.g. a structural
layer.
[0153] It is noted that the methods of forming the panel described
with respect to FIGS. 6a-6d, 7a-7d and 8a-8b may be applied to the
forming of the core as described with respect to FIGS. 9a-9c,
provided that the possibly outwardly tackiness or stickiness is
managed through e.g. a protective film and provided that the
pressure is applied correctly.
[0154] Hence, it is possible to provide a core, which can be wound
onto a roll, as schematically illustrated in FIG. 10. The core may
then be unwound from the roll and any type of structural layers may
be laminated to it under pressure Fp to produce a substantially
continuous blank, such as wood or laminate decorative layers or
backing layers.
[0155] It is noted that the descriptions above on production of a
blank may be applied to a panel blank as well, in the event that it
is desirable to produce the panel blank directly, rather than
forming it by dividing a blank into several smaller pieces.
[0156] The combination of wood blocks and expanded polymer material
blocks, is to be understood as an example of an implementation of
the present disclosure. More generally, the wood blocks may be seen
as a first material block and the expanded polymer material blocks
may be seen as a second material block.
[0157] The first material blocks may thus be provided from another
material than wood, such as e.g. a polymer/plastic material. The
blocks may be formed from a composite material comprising a binder,
such as a polymer matrix, one or more fillers and/or one or more
reinforcing fibers.
[0158] Examples of fillers include one or more of wood chips, wood
particles, wood dust (saw dust, wood flour) or wood fibers; mineral
fillers (calcium, dolomite, etc); polymeric fillers (e.g. chunks or
particles of recycled polymer, rubbers or rubber-like
materials).
[0159] Examples of reinforcing fibers include one or more of glass
fibers, carbon fibers, plant fibers (e.g. hemp, grass, bamboo or
wood fibers or wood strands), or polymer fibers.
[0160] Hence, the first material blocks may be formed of so-called
"engineered wood" or "reconstituted wood", which as such is known
from e.g. WO 2009/140136A2 and WO2010/082137A1, the entire contents
of which is hereby incorporated herein by reference.
[0161] Examples of polymer matrices include one or more of
thermoplastic material (polyethylene, polypropylene, etc.), epoxy,
polyurethane, thermosets (phenol, melamine, urea or combinations
thereof), acrylic and polyester.
[0162] The second material blocks may differ from the first
material blocks with respect to at least one of material type (i.e.
it may be formed from a completely different material), material
composition (i.e. it may be formed from the same materials as the
first material blocks, but with different proportions), material
density (i.e. it may be formed (e.g. expanded) to have a different
density than the first material blocks), material hardness (i.e. it
may be treated so as to achieve a higher or lower hardness) and
material elastic modulus. Typically, the first material blocks may
have a higher elastic modulus along a direction l which is
perpendicular or otherwise transverse to the principal direction L
of the core than the second material blocks, such that the blocks
as such are stiffer. This may be achieved by e.g. arranging
elongate fibers to extend substantially perpendicular to the
principal direction L of the core.
[0163] The second material blocks may have a substantially lower
density than the first material blocks, e.g. due to being
expanded.
[0164] In the alternative, the second material blocks may have a
substantially higher density than the second material blocks, e.g.
due to comprising a relatively heavy filler. This may be desirable
in order to reduce sound.
[0165] While the first material blocks may be selected to provide
the necessary bending strength and joining strength, the second
material blocks may be selected to provide another property, such
as weight reduction, cost reduction and/or sound reduction.
[0166] The second material blocks referred to above may be formed
of any material, which may be less costly, have lower density
and/or lower tensile strength in the direction which is parallel
with the principal direction of the wood fibers of the wood
blocks.
[0167] Hence, the second material blocks may comprise an engineered
wood product.
[0168] A first example of such a material is a so-called LDF (low
density fiberboard) or VLDF (very low density fiberboard), which
may be a board which is formed through moulding or compression
moulding of wood chips, particles and/or dust. It is possible to
mould such material during wet or moist condition, in which no or
very little additional binder need to be added.
[0169] For example, an LDF board may be used having a density of
160-500 kg/m3 may be used.
[0170] In the alternative, a VLDF board may be used having a
density of 200-300 kg/m3. LDF and VLDF boards are known from
Rowell, R. et al: "Dimensionally Stabilized Very Low Density
Fiberboard", Wood and Fiber Science, 27 (4). pp. 428-436 (1995),
the entire content of which is hereby incorporated herein by
reference.
[0171] In yet another alternative, a ULDF (ultra low density fiber)
board may be used having a density of 50-200 kg/m3. Such fiber
boards are known through Xie, Y. et al: "Manufacture and Properties
of Ultra-Low Density foamed Fibreboard from Wood Fibre",
BioResources 6 (4), 4055-4066 (2011) the entire contents of which
is hereby incorporated herein by reference.
[0172] Hence, fiber boards having low, very low or ultra low
density may be provided substantially without binder (wet/moist
compression moulding), with binder and/or with additional
additives.
[0173] It is also possible to replace or complement the expanded
polymer material blocks or second material blocks with non-expanded
composite polymer material blocks comprising a polymer matrix and
fillers, such as e.g. wood chips, wood particles, wood dust (saw
dust, wood flour) or wood fibers, mineral fillers (calcium,
dolomite, etc), polymeric fillers (e.g. recycled polymers, rubbers
or rubber-like materials).
[0174] Exposed portions of second material blocks of wood fiber
(e.g. LDF, VLDF, ULDF) or filled polymer material may also be
provided with surface treatment in order to improve e.g. strength,
friction (reduce) or wear properties. Such treatment may include
the application of penetrating or coating forming matter, such as
lacquer and/or thermosetting polymers.
[0175] At least one of the material block types may be flexible
enough to allow the core to bend so as to provide an angle of more
than 5.degree., preferably more than 10.degree., more than
15.degree., more than 20.degree. or more than 25.degree. between
major surface normals of a pair of adjacent (but with at least one
other material block in between) material blocks of the same
type.
[0176] The bending may also be rendered possible, or facilitated,
by a longitudinal space between immediately juxtaposed first and
second material blocks. Such a space may be on the order of 0.1-5
mm, preferably 0.5-3 mm, most preferably 1-3 mm.
[0177] Also, where relevant, the web 20, 21 may be flexible enough
to allow such bending as described above.
[0178] It is understood that the core may comprise two or more
types of material blocks, which may be arranged alternatingly in
the principal direction L of the core and with their principal
directions I substantially perpendicular to the principal direction
L of the core.
[0179] It is also understood that while the above blanks, panel
blanks and floor panels have been disclosed as a three layer
structure (decorative layer, core layer and balancing layer), it is
possible to use the core of the present disclosure also for
two-layer panels, i.e. panels comprising a decorative layer and a
core layer. Such panels may be installed and glued to a subfloor.
They may be flexible to such an extent as to absorb, or conform to,
height variations of the subfloor.
[0180] In specific embodiments, the following core types may be
mentioned:
[0181] a combination of wood blocks (first material) and filled or
non-filled expanded polymer material blocks (second material);
[0182] a combination of wood blocks (first material) and low
density fiber board (ULDF, VLDF, LDF) blocks (second material);
and
[0183] a combination of wood blocks (first material) and filled
non-expanded polymer material blocks (second material).
[0184] Such cores may be used for floor panels having any type of
decorative layer and balancing layer disclosed herein.
* * * * *