U.S. patent application number 11/192552 was filed with the patent office on 2006-02-16 for flooring products and methods of making the same.
This patent application is currently assigned to Mannington Mills, Inc.. Invention is credited to Hao A. Chen, Richard Judd.
Application Number | 20060032175 11/192552 |
Document ID | / |
Family ID | 35735962 |
Filed Date | 2006-02-16 |
United States Patent
Application |
20060032175 |
Kind Code |
A1 |
Chen; Hao A. ; et
al. |
February 16, 2006 |
Flooring products and methods of making the same
Abstract
A plank is described wherein the plank comprises a core, and
optionally, a print layer, and optionally an overlay. The core
includes from about 30 wt % to about 95 wt % at least one polymeric
material, by weight of the core, and from about 5 wt % to about 70
wt % of least one natural fiber or flour, by weight of the core,
wherein the core includes a top surface and a bottom surface, and
opposing sides, wherein said plank is substantially moisture
resistant, having a swelling property of from about 0.5% to about
5% by NALFA Thickness Test Section 3.2 LF 01-2003 standard, and
wherein said plank includes a bow of from about 0.5% to about 4%.
In addition, a method of making the plank is further described.
Inventors: |
Chen; Hao A.; (Chaddsford,
PA) ; Judd; Richard; (Newark, DE) |
Correspondence
Address: |
KILYK & BOWERSOX, P.L.L.C.
400 HOLIDAY COURT
SUITE 102
WARRENTON
VA
20186
US
|
Assignee: |
Mannington Mills, Inc.
|
Family ID: |
35735962 |
Appl. No.: |
11/192552 |
Filed: |
July 29, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60592488 |
Jul 30, 2004 |
|
|
|
Current U.S.
Class: |
52/578 |
Current CPC
Class: |
B32B 3/06 20130101; E04F
2201/0153 20130101; B32B 7/02 20130101; B32B 21/06 20130101; B32B
2262/067 20130101; B32B 21/08 20130101; B32B 2307/734 20130101;
B32B 27/18 20130101; B32B 23/08 20130101; B32B 2260/046 20130101;
B32B 3/04 20130101; B32B 2307/102 20130101; B32B 2250/24 20130101;
B32B 27/32 20130101; B32B 7/12 20130101; E04F 15/02033 20130101;
B32B 29/06 20130101; B32B 2419/04 20130101; B32B 23/14 20130101;
E04F 15/02 20130101; B32B 2264/067 20130101; B32B 2264/102
20130101; B32B 2307/4023 20130101; B32B 2307/724 20130101; B32B
27/20 20130101; B32B 27/304 20130101; B32B 2260/026 20130101; E04F
2201/0115 20130101; E04F 15/10 20130101; B32B 27/40 20130101; B32B
3/26 20130101; B32B 2307/4026 20130101; B32B 2307/7265 20130101;
B32B 29/00 20130101; B32B 21/02 20130101; B32B 3/30 20130101; B32B
21/14 20130101; B32B 29/005 20130101 |
Class at
Publication: |
052/578 |
International
Class: |
E04C 3/00 20060101
E04C003/00 |
Claims
1. A plank comprising: a core comprising from about 30 wt % to
about 95 wt % of at least one polymeric material, by weight of said
core, and from about 5 wt % to about 80 wt % of at least one
natural fiber or flour, by weight of said core, wherein said core
has a top surface and a bottom surface, and opposing sides, wherein
said plank is substantially moisture resistant, having a swelling
property of from 0.5% to about 5%, by NALFA Thickness Test Section
3.2 LF 01-2003 standard, and wherein said plank includes a downward
bow or dome of from about 0.5% to about 4%.
2. The plank of claim 1, wherein said plank has a density of from
about 60 lbs/ft.sup.3 to about 85 lbs/ft.sup.3.
3. The plank of claim 1, wherein said plank has a glass transition
temperature of about -50.degree. C. or higher.
4. The plank of claim 3, wherein said glass transition temperature
is from about -45.degree. C. to about 105.degree. C.
5. The plank of claim 1, wherein said core has a thickness of from
about 5 mm to about 20 mm, a width of from about 2 cm to about 30
cm, and a length of from about 30 cm to about 130 cm.
6. The plank of claim 1, wherein said core has a plurality of
cavities.
7. The plank of claim 1, wherein two sides of said core are tapered
or have beveled edges, wherein said sides are opposite to each
other.
8. The plank of claim 1, wherein said polymeric material comprises
a melt index of from about 0.4 to about 20 grams/10 minutes.
9. The plank of claim 1, wherein said polymeric material includes a
melt index of from about 0.8 to about 3 grams/10 minutes.
10. The plank of claim 1, wherein said polymeric material comprises
a polyolefin group.
11. The plank of claim 10, wherein said polyolefin group comprises
a polyethylene.
12. The plank of claim 1, wherein said polymeric material comprises
a polypropylene, a polyvinyl chloride, a copolymer of PVC, or a
combination thereof.
13. The plank of claim 1, wherein said polymeric material comprises
at least one thermoplastic material, at least one plasticizer, and
at least one coupling agent.
14. The plank of claim 13, wherein said plasticizer is present in
an amount of less than about 20% by weight of said core.
15. The plank of claim 1, wherein said natural fiber or flour
includes a particle size of from about 50 mil or less.
16. The plank of claim 1, where in said natural fiber or flour has
a particle size of from about 30 mil or less.
17. The plank of claim 1, wherein said natural fiber or flour
includes from about 10 wt % to about 40 wt % of a fiber or flour
having a size of from about 20 mil to about 30 mil; from about 10
wt % to about 30 wt % of a fiber or flour having a size of from
about 15 mil to about 20 mil; from about 10 wt % to about 30 wt %
of a fiber or flour having a size of from about 5 mil to about 15
mil, and from about 0 wt % to about 20 wt % of a fiber or flour
having a size of about 5 mil or less.
18. The plank of claim 1, wherein said natural fiber or flour
comprises a moisture content of about 1 wt % or less.
19. The plank of claim 1, wherein said natural fiber or flour
comprises wood, a cellulose source other than wood, or a
combination thereof.
20. The plank of claim 1, wherein said plank has a swelling
property of from 0.5% to about 3% by NALFA Thickness Test Section
3.2 LF 01-2003 standard.
21. The plank of claim 1, wherein said plank comprises a bow of
from about 0.5 inch to about 3.5 inches.
22. The plank of claim 1 further comprising at least one
lubricant.
23. The plank of claim 22, wherein said lubricant in present in an
amount of from about 1% to about 5% or more, by weight of said
core.
24. The plank of claim 22, wherein said lubricant comprises a
polyester lubricant.
25. The plank of claim 22, wherein said lubricant comprises a
polyolefin wax, an amide wax, a montanic acid ester, a metallic
stearate, a calcium stearate, a zinc stearate, a metal salt of a
long chain carboxylic acid, a paraffin, or any combination
thereof.
26. The plank of claim 1 further comprising at least one
compatibilizer or coupling agent.
27. The plank of claim 26, wherein said compatibilizer or coupling
agent is present in an amount of from about 0.5 wt % to about 5 wt
%, by weight of said core.
28. The plank of claim 26, wherein said compatibilizer or coupling
agent comprises a maleic anhydride.
29. The plank of claim 1, further comprising a laminate, wood
veneer, vulcanized cellulose layer, or a combination thereof on
said top surface.
30. The plank of claim 1, further comprising an underlay layer
located and affixed between bottom surfaces of a top layer and said
top surface of said core.
31. The plank of claim 30, wherein said underlay comprises an
aminoplast resin impregnated paper.
32. The plank of claim 30, wherein said underlay comprises Kraft
paper impregnated with an aminoplast resin.
33. The plank of claim 30, wherein an adhesive is present between
said cores and said underlay layer in order to affix said underlay
layer to said core.
34. The plank of claim 30, further comprising a printed design.
35. The plank of claim 30, further comprising a protective layer
affixed to said top surface of said top layer.
36. The plank of claim 35, wherein said protective layer comprises
an aminoplast resin impregnated overlay paper and aluminum oxide
imbedded on the top surface of said paper.
37. The plank of claim 35, wherein said protective layer comprises
an aminoplast resin impregnated overlay paper.
38. The plank of claim 30, wherein said plank includes a bow of
from about 2.5 inches to about 3.2 inches.
39. The plank of claim 30, wherein said top layer comprises a
decorative element.
40. The plank of claim 30, wherein said top layer is embossed with
a design.
41. The plank of claim 1, wherein said bottom surface of said core
is thermally treated.
42. The plank of claim 1, further comprising at least one design
layer.
43. The plank of claim 42, wherein said design layer has the design
of natural wood, stone, ceramic, brick, or tile.
44. The plank of claim 42, wherein said plank further comprises a
layer that has texture or said top surface of core has a textured
surface or both.
45. The plank of claim 44, wherein said design on said design layer
and said texture are in register.
46. The plank of claim 44, wherein said texture simulates the
texture present in natural wood, stone, ceramic, brick, or
tile.
47. A floor comprising a plurality of the planks of claim 1 joined
together.
48. The floor of claim 47, wherein the planks are joined together
by a mechanical locking system.
49. The floor of claim 47, wherein the planks are joined together
by a bonding agent.
50. The floor of claim 47, wherein the planks are joined together
by a tongue and grove connection.
51. The floor of claim 47, wherein the planks are joined together
by a grove and spline system.
52. The floor of claim 47, wherein said floor is a floating floor.
Description
[0001] This application claims the benefit under 35 U.S.C.
.sctn.119(e) of prior U.S. Provisional Patent Application No.
60/592,488 filed Jul. 30, 2004, which is incorporated in its
entirety by reference herein.
[0002] The present invention relates to wood/polymer composite
products, such as flooring products and methods to make the same.
The present invention particularly relates to a plank or tile core
that is structurally durable in providing excellent wear and
durability properties as well as water resistance. The methods to
make the product offer design versatility with superior
sustainability by optionally incorporating high amounts of post
consumer or post industrial recycled material into the flooring
products without compromising the performance and aesthetics. Also,
proper selections of the wear surface material for the product can
greatly reduce the life-cycle cost by minimizing the frequency of
maintenance.
BACKGROUND OF THE INVENTION
[0003] Commercially available floorings, such as laminate flooring
(using high or medium density fiberboard or particle board as the
core layer), have gained overwhelming success in the flooring
market. The growth rate of the laminate flooring has remained in
the double digits since the product was introduced in the United
States market. The success of this product is credited to certain
properties such as stain resistance, wear resistance, fire
resistance, good cleanability, and the ability to use just about
any type of printed design. In addition, the overall emission of
organic compound vapor is low and the laminate flooring is
considered color stable and environmentally friendly over other
competing flooring products.
[0004] One concern with commercially available laminate flooring is
the moisture resistance of the finished product and the sensitivity
of the raw materials (high or medium density fiberboard, paper, and
particle board) to moisture during the manufacturing process. In
some instances, the moisture can lead to some serious quality
control issues and application restraints. For instance, and just
to name a few, the higher moisture content in the product, such as
in the particle board or fiberboard, can cause blistering and
adhesion failure of the melamine surface to the core. Also, higher
moisture contents can lead to dimensional instability of the
finished product, which then results in the cupping or doming of
the product, which is extremely undesirable, especially when
installers are laying down the flooring. Also, excessive moisture
contents can create edge peaking due to the swelling of the product
and such edge peaking can result in edge chip-off or premature
wear-out or can soil more quickly. The susceptibility to moisture
content also leads to some installers not wishing to place such
laminate flooring in areas which are subject to having water on the
surface of the floor, such as in the kitchen and bathroom
areas.
[0005] The suppliers of such laminate flooring have appreciated the
problems associated with their products and have attempted to
overcome these problems by developing laminate flooring having
better moisture resistance by using melamine, phenolic, or
isocyanate binders to partially replace urea resins present in the
laminate flooring. While this improvement has made the product more
moisture resistant, the current commercially available laminate
floorings are still prone to moisture damage. For instance,
laminate floor thickness can swell by more than 10% and water
absorbency can exceed more than 15% according to the 24 hours water
absorption test. Another attempted solution at the moisture
resistance weaknesses of current laminate flooring has led some
manufactures to apply a water-repellant material on the upper edges
of the tongue and groove areas which further serve to resist any
moisture penetration through joints. Still another attempted
solution involves applying silicone caulk to seal the edges and
voids of the laminate perimeter where the laminate flooring meets
the wall. However, if very stringent installation instructions are
not followed, the laminate flooring will still be subjected to
moisture damage.
[0006] Another weakness of laminate flooring is its susceptibility
to break or chip at the corners of edges and the tongue and the
groove profile because fibers in the high density fiber board are
not cohesively bonded together with chemicals. Rather, they are
pressed together primarily by tremendous pressure and heat.
[0007] Commercially available flooring that is an acrylic
impregnated wood flooring is available. A typical acrylic
impregnated wood flooring is produced by: 1) impregnating liquid
acrylic monomer or other suitable monomers into raw wood veneer,
wherein the liquid monomer is forced into the pores of the wood; 2)
followed by polymerizing or hardening the acrylic monomer by
thermal or free radical polymerization such as gamma radiation or
heat; 3) bonding the impregnated veneer with polyurethane adhesive
to the wood veneer base to form the finished product; and 4)
optionally choosing a glass fiber layer in between the top surface
and the base to produce a more dimensionally stable product.
Typical acrylic impregnated wood flooring is not an environmental
and operational friendly product. It takes a long time to
impregnate the liquid acrylic monomer into pores of the wood
veneer. It is often difficult or impossible to penetrate the liquid
fully to the desirable depth or to penetrate uniformly into the
pores of the wood. In addition, operators need to exercise
tremendous caution for safely handling noxious liquid acrylic
monomer and pay attention to the environmental consideration and
government regulations. Due to such a time consuming and a labor
intensive process, the product normally is very expensive.
Consequently, only limited buyers can afford to use it. However,
the acrylic impregnated wood layer offers excellent moisture
resistance properties, has minimal indentation, and good wear, and
durability properties. It is ideally used in high traffic
areas.
[0008] Accordingly, there is a need to develop a new category of
flooring which overcomes the above weaknesses and disadvantages of
current commercially available floorings.
SUMMARY OF THE INVENTION
[0009] A feature of the present invention is to provide a plank
which can be used in a surface covering system. The plank is based
on a wood/plastic composite as the core, wherein fiber or flour
portions in the core are preferably encapsulated by the polymer
portion, and which provides improved moisture resistance, and is
not susceptible to damage caused by moisture.
[0010] Another feature of the present invention is to provide a
plank and surface covering system which is versatile for many
decorative and wear surfaces (e.g., veneers--oak, maple, ash,
beech, cherry, hickory, and other wood styles, and e.g., laminate
overlay, direct print, transfer printing, vulcanized paper, and the
like) depending upon the needs of markets.
[0011] A further feature of the present invention is to provide a
flooring system that has beneficial sustainability and life cycle
cost.
[0012] An additional feature of the present invention is to provide
a surface covering system having flexibility in shape, size, and
joint systems depending upon customer preference, installation ease
and familiarity, and maintenance ease.
[0013] Still another feature of the present invention is to provide
a surface covering system which has significant improvements in
wear, rupture, chipping and breakage resistant properties, such as
indentation, abrasion, appearance retention and chemical and stain
resistance and the like.
[0014] Another feature of the present invention is to provide a
surface covering system which is a higher value (better performance
and lower cost) than the impregnated wood flooring.
[0015] Another feature of the present invention is to provide a
flooring system that has great flexibility in choosing the type of
woods and polymers and its ratio of mixture.
[0016] Another feature of the present invention is to provide a
flooring system that can alleviate the requirement of a balance
layer on the back of the product.
[0017] Also, a feature of the present invention is to provide a
surface covering system which has the ability to tolerate some
imperfections in the sub-floor or substrate and thus avoid
telegraphing the imperfections on the surface covering itself.
[0018] A further feature of the present invention is to provide a
surface covering system which has excellent dimensional stability
and flammability resistance and the like.
[0019] Additional features and advantages of the present invention
will be set forth in the description which follows, and in part
will be apparent from the description, or may be learned by
practice of the present invention. The features and other
advantages of the present invention will be realized and attained
by means of the elements and combinations particularly pointed out
in the written description and appended claims.
[0020] To achieve these and other advantages and in accordance with
the purposes of the present invention, as embodied and broadly
described herein, the present invention relates to a plank, wherein
the plank has a core comprising at least one polymeric material, at
least one type of natural fiber or flour, wherein the core has a
top surface and a bottom surface, wherein the core is substantially
moisture resistant, having a swelling property (based on thickness)
of from about 0.5% to about 5%, and wherein the core includes a
downward bow of from about 0.5% to about 3.5% of the length of the
plank. Optionally, the core includes a lubricant and/or a
compatibilizer/coupling agent. Furthermore, optionally, affixed to
the top surface of the core can be a print layer, wherein the print
layer has a top surface and a bottom surface. Also, a protective
layer can be affixed to the top surface of the print layer. The
plank can optionally contain an underlay layer located and affixed
between the bottom surface of the print layer and the top surface
of the core. Furthermore, wood veneers such as oak, maple, ash,
pine, cherry, hickory, and the like can be affixed as a top layer
to the top surface of the core, wherein the top layer has a top
surface and a bottom surface. Also, a radiation cured urethane
acrylate coating or other wear resistant layer can be affixed to
the top surface of the top layer. Furthermore, a direct digital
design of any natural product or art work can be printed to the top
surface of the core, wherein the radiation cured (or e-beam cured)
urethane acrylate coating(s) or other wear resistant layer(s) can
be affixed to the top surface of the top layer. The present
invention further relates to a method of making a plank and can
involve the step of extruding at least one polymeric material, at
least one type of natural fiber or flour, and optionally, a
lubricant and/or a compatibilizer/coupling agent into the shape of
a core and optionally affixing a laminate on the core, wherein the
laminate comprises an overlay layer affixed to the top surface of a
print layer and optionally an underlay layer affixed to the bottom
surface of the print layer.
[0021] Also, the present invention relates to a method of making a
plank by printing a design directly on the top surface of the plank
using any number of printing techniques, such as embossing gravure
printing, transfer printing, digital printing, flexo printing, and
the like. The method includes applying a protective coating on top
of the printed design, such as a polyurethane type coating with or
without wear resistant particles in the coating.
[0022] A further embodiment of the present invention relates to
making a plank for flooring by co-extrusion techniques, which
involves extruding at least one polymeric material, at least one
type of natural fiber or flour, and optionally a lubricant and/or a
compatibilizer/coupling agent into the shape of the core and also
extruding a layer containing at least one thermoplastic material
with one or more pigmented compounds on top of the extruded core,
wherein the layer simulates a design, such as wood grain.
[0023] The present invention also relates to planks having the
above-described characteristics.
[0024] It is to be understood that both the forgoing general
description and the following detailed description are exemplary
and explanatory only and are intended to provide a further
explanation of the present invention, as claimed.
[0025] The accompanying drawings, which are incorporated in and
constitute a part of this application, illustrate several
embodiments of the present invention and together with the
description serve to explain the principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic diagram showing a side view of one
embodiment of the plank of the present invention.
[0027] FIG. 2 is a schematic diagram showing a side view of a
spline design which can be used in the present invention.
[0028] FIG. 3 is a schematic diagram of a sectional view showing
another embodiment of the plank of the present invention.
[0029] FIG. 4 is a schematic diagram showing a groove design for a
plank of the present invention.
[0030] FIG. 5 is a partial side view of one type of tongue and
groove system that can be used in the planks of the present
application.
[0031] FIG. 6 shows a side view of a plank which is finish sanded,
then wrapped with a laminate layer or layers and then cut to have a
tongue and groove system.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0032] For purposes of the present invention, a floor panel, or
plank includes, but is not limited to, any shape or size floor
panel. In other words, the floor panel can be rectangular,
triangular, square, hexagonal, and octagonal or have any number of
sides. Also, the floor panel can have other geometrical designs,
such as curves and the like. As long as the floor panels can be
joined together in some fashion, the present invention can be used.
Thus, for purposes of the present invention, floor panel includes
these various shapes and designs. In general, the present invention
relates to a plank which contains a core including from about 30 wt
% to about 95 wt % of at least one polymeric material, by weight of
the core, and from about 5 wt % to about 80 wt % of at least one
natural fiber or flour, by weight of the core. Other ranges include
from about 15 wt % to about 75 wt %, or from about 25 wt % to about
65 wt %, or from about 35 wt % to about 65 wt %, or from about 45
wt % to about 65 wt % of at least one natural fiber or flour, by
weight of the core. This core has a top surface, a bottom surface,
and generally at least four sides or edges. The core of the present
invention is substantially moisture resistant, having a swelling
property of from 0.5% to about 5%, by NALFA Thickness Swell Test
(Section 3.2 LF 01-2003 Standard) (other ranges for moisture
resistance as determined by the swelling property are from 1.0% to
4%, or from 2.0% to 4%), and wherein the core includes a downward
bow of from about 0.5% to about 3.5% of the length of the plank.
Other ranges for the downward bow are from 1.0% to 3%, or 1.5% to
3%, or 2.0% to 3%.
[0033] The planks of the present invention can have a density of
from about 58 lbs./ft.sup.3 to about 73 lbs./ft.sup.3. Preferably,
the planks of the present invention include a density of from about
60 lbs./ft.sup.3 to about 70 lbs./ft.sup.3. The density of the
planks of the present invention is measured by Method 1:
measurement of weight of a given volume of the product. Weight is
measured using a balance reading to 0.0001 gram. Volume is
determined by measurement of dimensions using calipers reading to
0.001,'' or Method 2: calculation using specific gravity of
HDPE=0.93 g/cc and PP=0.91 g/cc with wood density=cellulose=1.27
g/cc and lubricant package at 1.1 g/cc.
[0034] In one example, the plank of the present invention does not
include a backing layer. The permanent downward bow of from about
0.5% to about 3.5% of the length of the plank can counteract for
having no backing layer. This bowing can be achieved, for instance,
by heat-treating the plank (e.g., heat treating the bottom surface
of the plank) in order to provide a sufficient bow (camber or dome)
to counteract any dimensional change of a top layer (if any) on the
core from temperature and humidity in the environment. The heat
treatment, for example, can be at a temperature of from about
250.degree. F. to 1,000.degree. F. (e.g., 300.degree. F. to
800.degree. F. or 300.degree. F. to 500.degree. F.) for a time,
such as 3 seconds to 1 minute (e.g., 3 seconds to 25 seconds).
[0035] The planks of the present invention can have a glass
transition temperature (Tg) of greater than about -50.degree. C.
Preferably, the glass transition temperature of the plank is from
either -45 to -15 deg C. (High Density Polyethylene) from -30 to
+20 deg C. (Polypropylene) or from 75 to 105 deg C. (polyvinyl
chloride). The glass transition temperature can be from -45 to 105
deg C. The polymeric material of the present invention can be
present in an amount of from about 30 wt % to about 95 wt % of the
weight of the core. The polymeric material can have a melt index of
from about 0.4 to about 20 grams. Preferably, the polymeric
material has a melt index of from 0.8 to about 3 grams. The amount
of polymeric material can be from 40 wt % to 90 wt % or from 50 wt
% to 80 wt %, based on the weight of the core.
[0036] The polymeric material of the present invention can be one
or more polymers having a polyolefin group, such as polyethylene.
Other exemplary polymers include, but are not limited to,
polypropylene, polyvinyl chloride, copolymer of PVC, and also other
suitable thermoplastics.
[0037] In more detail, the polymeric material in the core can be at
least one thermoplastic material. Generally, any polymeric
material, combinations thereof, alloys thereof, or mixtures of two
or more polymeric materials can be used for the polymeric material
of the core. Generally, the polymeric materials are thermoplastic
materials that include, but are not limited to, vinyl containing
thermoplastics such as polyvinyl chloride, polyvinyl acetate,
polyvinyl alcohol, and other vinyl and vinylidene resins and
copolymers thereof; polyethylenes such as low density polyethylenes
and high density polyethylenes and copolymers thereof; styrene such
as ABS, SAN, and polystyrenes and copolymers thereof; polypropylene
and copolymers thereof; saturated and unsaturated polyesters;
acrylics; polyamides such as nylon containing types; engineering
plastics such as acetyl, polycarbonate, polyimide, polysulfide, and
polyphenylene oxide and sulfide resins and the like. One or more
conductive polymers can be used to form polymeric material of the
plank, which has applications in conductive flooring and the like.
The thermoplastic polymers set forth in Kirk-Othmer (3rd Edition,
1981) at pp. 328 to 848 of Vol. 18 and pp. 385-498 of Vol. 16,
(incorporated in their entirety by reference herein) can also be
used as long as the resulting plank has sufficient strength for its
intended purpose.
[0038] Preferably, the thermoplastic material is a polyolefin
including polyethylene or polypropylene, and rigid polyvinyl
chloride (PVC), semi-rigid or flexible polyvinyl chloride may also
be used. Preferably, the olefins or the rigid PVC possesses good
impact strength, ease of processing, high extrusion rate, good
surface properties, excellent dimensional stability, and
indentation resistance. The flexibility of the thermoplastic
material can be imparted by using at least one liquid or solid
plasticizer which is, preferably, present in an amount of less than
about 20 phr, and, more preferably, less than 1 phr (e.g., less
than 20% by weight of the core), especially in the case of PVC. A
typical rigid PVC compound used in the present invention to form
the polymeric material of the core can also include, but is not
limited to, pigments, impact modifiers, stabilizers, processing
aids, lubricants, fillers, other conventional additives, and the
like.
[0039] The polymeric material to be processed can be in powder,
liquid, cubed, pelletized form and/or any other extrudable form.
Also, the polymeric material can be virgin, recycled, or a mixture
of both. Furthermore, the polymeric material can be incorporated
with a blowing agent(s) or a mechanically injected gas during the
extrusion process to make a cellular foam structure core.
[0040] The polymeric materials used to form part of the core can be
polyolefin and polyvinyl chloride. Polyolefin is preferably, High
Density Polyethylene or Polypropylene. PETROTHENE LB 0100-00 can be
used and is a high density polyethylene reactor powder. LB0100-00
provides excellent polymer dispersion, lower extruder amperage, and
increased extruder output rates versus pellets of equivalent melt
index and density in wood plastic composites.
[0041] Physical Properties for LB 0100-00 TABLE-US-00001 ASTM
Property Value Units Method Melt Index 0.50 g/10 min D 1238 Density
0.952 g/cc D 1505 Tensile Strength @ Break 3,960 psi D 638
Elongation @ Break >600 % D 638 Flexural Modulus 185,000 psi D
790 Tensile Impact 120 ft-lb/in. D 1822 Low Temperature
Brittleness, F.sub.50 <-76 .degree. C. D 746 Heat Deflection
Temperature @ 75 .degree. C. D 648 66 psi Vicat Softening Point 123
.degree. C. D 1525 Hardness, Shore D 66 D 2240 Environmental Stress
Crack Resistance, F.sub.50 Bent Strip 35 hrs D 1693 Bottle >500
hrs D 2561
[0042] Exxon Mobil PLTD 1765 Homo-polymer can be used and is a
medium melt flow rate polypropylene homo-polymer.
[0043] Physical Properties PLTD 1765 TABLE-US-00002 ASTM Property
Value Units Method Melt Index 4.0 g/10 min D 1238 Density 0.9 g/cc
D 792 Tensile Strength @ Yield 4,900 psi D 638 Elongation @ Yield
10 % D 638 Flexural Modulus 220,000 psi D 790 Izod Impact 0.8
ft-lb/in. D 256 Low Temperature Brittleness, F.sub.50 <-76
.degree. C. D 746 Heat Deflection Temperature @66 psi 91 .degree.
C. D 648
[0044] PVC resin can be used and is a suspension grade or mass
polymerization grade homopolymer resin having a preferred molecular
weight as reflected by an inherent viscosity of from about 0.88 to
about 1.0 inherent viscosity. In general, a higher molecular weight
polymer is preferred from the standpoint of processing stability
and, preferably, the molecular weight distribution and particle
size distribution are narrow in order to provide a good balance
between processability and properties. Also, a high, uniform
porosity of the resin particles are preferred to optimize
compounding and processing aspects, including the fast and uniform
absorption of any stabilizer that is present as well as other
ingredients during compounding.
[0045] The polyvinyl chloride can have the following properties:
TABLE-US-00003 GEON COMPOUND ASTM METHOD 87150 Type Cube Cell
Classification D1784 13344-C Specific Gravity 0.2 D792 1.45
Hardness-Durometer Shore D 3 D2240 82 Tensile Properties - Strength
PSI D638 6000 Tensile Properties - Modulus PSI D638 390000 Flexural
Properties - Strength PSI D790 11000 Flexural Properties - Modulus
PSI D790 370000 Heat Deflection Temperature F. D648 160 Unannealed
@ 1.82 MPa (264 PSI) Coefficient of Linear Expansion D696 3.4
.times. 10-5 in./in. F. Notched IZOD Ft.lb./in. of notch @ D256 3
23 C. (73 F.) Impact Properties - Drop Impact D4226 in.lb/mil @ 375
F. melt T. 1/4'' Dart H.250 Method A 1.0 1/4'' Dart H.250 Method B
1.0 1/8'' Dart H.125 Method A 1.0 1/8'' Dart H.1250 Method B
1.0
[0046] Generally, this compound can have a melt temperature of from
about 360 to about 390.degree. F. Also, a stabilizer can be present
in the polymeric formulation that forms part of the core. A
preferred stabilizer is a butyl tin mercaptide stabilizer. In
addition, an impact modifier can be also present. Preferred impact
modifiers are acrylic-based from Rohm and Haas, an EVA-based impact
modifier known as Elvaloy.TM. from DuPont; and others such as
chlorinated polyethylene and acrylonitrile butadiene styrene, and
the like.
[0047] With respect to the above various tables and properties,
generally, the core can have any one or more of these properties or
can have any one or more of these properties that are within 25% or
within 10% of the stated property values provided. In addition, the
polymeric formulation can contain at least one processing aid,
which is, preferably, an acrylic based low molecular weight resin
such as Acryloid K-125 or K-175 from Rohm and Haas.
[0048] With respect to the natural fibers or flour, the natural
fibers or flour in the core is preferably present in an amount of
from about 5% to about 75% or to about 80 wt %, by weight of the
core. Preferably, the natural fibers have a reduced particle size.
This can be achieved, for instance, by pulverizing and classifying
the particle sizes. Generally, this pulverizing and the like forms
a wood flour. The natural fibers or wood flour can have a particle
size of about 50 mil or less and, more preferably, about 30 mil or
less. In one embodiment, the particle size is no less than 7 mil or
no less than 5 mil. In one embodiment, the particle size of the
natural fibers that are present are based on a particle size
distribution. In one embodiment, about 10 wt % to 40 wt % of the
particles have a particle size of from about 20 mil to 30 mil,
about 10 wt % to 30 wt % of the particles have a particle size of
from about 15 mil to 20 mil, about 10 wt % to 30 wt % of the
particles have a particle size of from about 5 mil to 15 mil, and
about 0 wt % to 20 wt % of the particles have a particle size of
about 5 mil or less. With respect to these particle sizes, it would
be difficult to have the size ranges as absolute values. Thus,
there may be particles outside these size ranges to a small extent,
such as less than 15% by weight of all particles, and more
preferably less than 10% by weight or less than 5% by weight of the
particles present.
[0049] The following particle size distribution can be used as an
example: TABLE-US-00004 Mesh Size Retained mil mm 30 35% 23 0.58 40
30% 16.5 0.42 50-60 30% 11.7-9.8 0.30-0.25 80 5% 7 0.18
[0050] As another example, the wood flour/fibers can have a
particle size ranging from that passing through 20 mesh screen to
that retained on 80 mesh screens. This 20/80 size fraction
corresponds to 180 microns to 850 microns particle size. More
preferably, the size range corresponds to the fraction passing
through a 20 mesh screen to that retained on a 60 mesh screen. This
size 20/60 size fraction corresponds to 250 microns to 850
microns.
[0051] Other weight percentages and particle size distributions or
any combination thereof can also be utilized.
[0052] The natural fibers or flour preferably have a moisture
content of about 1% or lower (by weight of fiber or flour). The
natural fiber or wood flour most preferably has a moisture content
of less than 0.5 wt %. The natural fibers can be from any wood
source, cellulose source, other natural sources, or any combination
thereof. Examples include, but are not limited to, wood (e.g.,
maple, oak, pine, cedar, hickory, spruce, poplar, ash, and the
like), bamboo, kenaf, jute, hemp, flax, sisal, cotton, coconut
flour, rice hull, and the like. As stated, generally, any natural
fiber can be used which is from trees, plants, parts thereof and
the like. For purposes of the present invention, natural fiber and
flour include the above in fiber form or flour form (i.e., particle
size). Synthetic fibers may also be used to enhance mechanical
properties such as flexural and tensile modulus of the product. The
higher aspect ratio (ratio of length to diameter), the better
enhancement of the properties. In addition to natural fibers and
flour, fillers that are not natural fiber or flour can be added to
the core formulation to further reduce product cost and to improve
impact properties. While any filler can be used as long as it is
compatible with the polymeric material and natural fiber or flour,
typical fillers include, but are not limited to, calcium
carbonate.
[0053] The natural fiber or flour can be virgin, recycled, or a
mixture of both. Furthermore, the natural fiber or flour can be
incorporated with a foaming agent(s) or a mechanically-injected gas
during the extrusion process to make a cellular foam structure
core.
[0054] In one example, the planks of the present invention can have
a thickness swelling property of about 3% or less, and, more
preferably, from about 0.5 to about 3% swelling. This is
significantly less than conventional laminates which have a
swelling of from 12 to 14%. The swelling property is measured by
immersing the sample in water for 24 hours according to the test
method NALFA Thickness Swell Test Section 3.2 LF 01-2003,
incorporated by reference herein.
[0055] The plank of the present invention, preferably, has a bow to
counteract any dimensional change of the top layer, such as a
laminate, on the core from temperature and humidity in the
environment. Preferably, the planks of the present invention,
especially those without a backing layer, are domed in order to
create an arch for purposes of achieving desired dimensional
stability.
[0056] The amount of dome can be dependent on the type of surface
layer utilized and the moisture content of the surface layer at the
time of wrapping. The amount of dome of the plank should
accordingly be adjusted so that the plank has its ability to
maintain flatness in its service environment. For instance, in one
example where a laminate overlay is utilized as the surface layer,
the plank can include a downward dome of from about 0.25 inch to
about 2.9 inches and preferably, from about 0.30 inches to about
2.5 inches. For a thin veneer (e.g., 0.006 inches) laminated on a
polyester backing system, the plank can have a bow of from about 1
inch to about 2 inches before being placed in the box. The bow
described above is measured vertically at the center of the plank
against a long straight edge that touches both ends. Preferably,
the plank of the present invention includes a bow of from about 1%
to about 4% of the length of the plank, based on 0% having no bow
and 100% being perpendicular to the center.
[0057] In another embodiment of the present invention, the planks
of the present invention have favorable flexibility which is very
suitable for laying the planks together on a floor since such
flexibility will conform to sub-floors more easily especially
imperfections in the sub-floor. In the present invention, in a
preferred embodiment, the planks of the present invention have a
plank sag of at least 25 inches and more preferably at least 30
inches. A suitable range for the plank sag is from about 25 inches
to about 45 inches. The plank sag is determined by a plank sag test
which determines how the plank will conform under gravity. The test
is conducted by using 6 foot long planks of the core without a
finished top layer (e.g., no laminate layer). The plank core is
clamped with C-clamps to a hedge of a horizontal platform (e.g., a
table). The plank core is clamped so that as much of the 6 foot
length can hang as possible. The amount that the plank sags at the
unclamped end from a horizontal plane is measured. As indicated,
this shows the flexibility of the product. The planks of the
present invention preferably have this plank flexibility in
association with the other properties set forth above. The planks
of the present invention have this preferred flexibility either
with a dome as described above or without a dome.
[0058] At least one lubricant can be present in the formulation.
The amount of lubricant can be any suitable amount, such as, for
example, from about 1 wt % to about 5 wt % or more, by weight of
the formulation. One example of such a lubricant is from Struktol
(Struktol TPW104). A lubricant such as a polyester lubricant can be
used.
[0059] The lubricant can include an internal lubricant and an
external lubricant. Preferred internal lubricants, which act
internally to alter the cohesive forces amongst the polymer chains
that result in lower melt viscosity without reducing the strength
properties of the resin, are metallic stearates such as calcium and
zinc salts of stearic acid. External lubricants, which act
externally to prevent resins from sticking to hot metal processing
machinery by reducing friction between the surfaces, are preferably
low-melting paraffin. Other examples of lubricants include
polyolefin wax, fatty acid amides, fatty acid esters, metal soaps
and salts of stearic acid and other organic acids, and the
like.
[0060] The core can include at least one compatibilizer/coupling
agent for improving impact strength, heat distortion temperature,
tensile and elongation characteristics and modulus of elasticity
and lastly reducing moisture sensitivity. The amount of
compatibilizer can be from about 0.5% to about 5% by weight. An
example of a compatibilizer/coupling agent that can be used in the
present invention is maleic anhydride.
[0061] Preferably, the core is rigid in nature and includes the
following range of preferred properties: impact resistance, static
load resistance, indentation resistance, moisture insensitivity,
pre-profiled configuration, and the like.
[0062] The dimensions of the core can practically be any shape
(e.g., square, rectangle, curved, and the like) or size as long as
such material can be extruded as one piece or multiple pieces. For
instance, the core can include a thickness of from about 3 mm to
about 50 mm, a width of from about 2 cm to about 60 cm, and a
length of from about 30 cm to about 215 cm. Also, the top surface
of the core can, optionally, have a textured surface on the top
surface as part of the core which is extruded through the die. A
mechanical embossing row can be located behind the cooling
calibrator and after the extrusion die to achieve surface texturing
of the extruded core. Any variety of textures can be created by
this method on the core such as wood grains and the like.
[0063] Also, as an option, the core can be 100% solid or can have
one or more cavities or cells which are located between the upper
and lower surfaces of the core. The solid core is preferred since
it enhances the impact strength and the indentation property of the
product. The extruded core preferably has the thickness from about
3 mm to about 25 mm, preferably, about 6 mm to about 10 mm. The
width of the plank has the dimension of 50 mm to 500 mm, preferably
has the width about 75 mm to 305 mm. While the cavities or cells
are optional, the extruded core can have cavities having dimensions
of 3 mm to about 16 mm in height, preferably, about 7.6 mm in
height by about 6 mm by about 20 mm in width, preferably, about 7.6
mm in width, and can be separated by a wall, preferably, a solid
thermoplastic material, having a thickness of from about 1.0 mm to
about 3.02 mm, preferably from about 1.27 mm to about 1.8 mm. The
optimal dimension of cavities is dependent upon the requirement of
the product withstanding the potential impact force of falling
objects. The cavities which are preferably present can be in any
shape such as rounded, oval, or rectangular. These cavities or
cells, preferably, exist across the entire distance of the core as
shown in FIG. 1. Another advantage is that wires, cables, fiber
optics, and/or piping can be run through the cavities which makes
installation of wiring and piping quite easy without the necessity
of putting holes through walls, or running wires underneath the
floor or in the ceiling. Further, if necessary, holes can be
drilled through the polymeric material and the natural fiber that
separate one cavity from another in order to have the wire or
piping go in a perpendicular direction when necessary.
Alternatively, for certain polymeric and natural fiber core pieces,
the cavities can be run in a perpendicular direction from the
remaining pieces in order to accommodate the direction that wiring
or piping may take when being placed in a room.
[0064] The cores which form the plank are preferably all made from
the same die design and thus they are uniform in appearance. Also,
the cavities which are preferably present in the core align with
the cavities in respective core pieces. Dowels, biscuits or other
equivalent material can be inserted into the cavities at the short
end of the plank in order to join an adjacent plank to create a
tight seal at each seam. This type of coupling system, though
optional, can further insure a very secure tight fitting floating
floor or other surface covering.
[0065] Though not necessary, the ends of the plank as well as the
tongue and/or groove can have a bonding agent applied to these
locations in order to seal or bond the planks together. Sealant
compositions such as tetrahydrofuran have the ability to work as a
bonding agent to join the planks of wood/PVC composition together.
In one of the examples that follow, the results show that by using
tetrahydrofuran or compositions like tetrahydrofuran, the joints of
the planks which have been attached with the use of this
composition leads to the formation of a bond between the planks.
This increases the overall bond strength of two adjoining boards
significantly. This bonding agent can be used not only with the
planks described above. One advantage of using a bonding agent like
tetrahydrofuran is that it is simple to use, and leaves no residue
on the surface after evaporation. Thus, no adhesive marks are left
on the surface of the planks. In addition, applying such bonding
agents like tetrahydrofuran is quite easy since it can be applied
by brush or spray or applicator tip using gravity or other force
such as squeezing an applicator bottle, and any excess is easily
removed unlike the application of some adhesives for tiles and the
like. Other examples of suitable bonding agents which have the
ability to bond the thermoplastic planks (e.g., PVC) include, but
are not limited to, methylene chloride and ketones and the like.
Examples of ketones include, but are not limited to, methyl ethyl
ketone, methyl amyl ketone, dipropyl ketone, methyl isobutyl
ketone, n-methyl pyrrolidone, dimethyl formamide, cyclohexanone,
nitrobenzene, and the like.
[0066] Another option is to use waterborne adhesive such as
polyvinyl acetate type to bond the faces of the exposed wood fiber
after the plank was machined with a tongue and groove joint
system.
[0067] Another optional aspect of the core is the presence of a
groove and/or a tongue design on preferably at least two sides or
edges of the core wherein the sides or edges are opposite to each
other. For instance, the core design can have a tongue design on
one edge and a groove design on the opposite edge, and it is
possible to extrude the core with a tongue and a groove
configuration on two edges and then machine the dimension of the
tongue and the groove to the tight tolerance of the joint system
required for easing connection. The typical dimensional tolerance
for the extrusion process is around 15-20 mils (0.015-0.020
inches), ranges which can be considered too broad for the
connection system. The subsequent machining process can bring the
tongue and the groove dimension within the tolerance of adequate
fit. It is also possible for machining both edges which are
opposite to each other having a groove design. The tongue or groove
can have a variety of dimensions, but, preferably, the groove which
is present on two opposite edges has an internal depth dimension of
from about 5 mm to about 12 mm and a height of from about 3 mm to
about 5 mm. The bottom width of the side having the groove is
slightly shorter than the upper width of the same side to ensure no
gap exists between planks after butting together. With respect to
the edges of the floor panels, which are joined together in some
fashion, the floor panels can have straight edges or can have a
tongue and groove design or there can be some intermediate
connecting system used to join the floor panels together such as a
spline or other connecting device. Again, any manner in which floor
panels can be joined together is embodied by the present
application. For purposes of the present invention, the floor panel
can have a tongue and groove design or similar connecting design on
the side edges of the floor panel. Examples of floor panel designs,
shapes, and the like that can be used herein include, but are not
limited to, the floor panels described in U.S. Pat. Nos.:
6,101,778; 6,023,907; 5,860,267; 6,006,486; 5,797,237; 5,348,778;
5,706,621; 6,094,882; 6,182,410; 6,205,639; 3,200,553; 1,764,331;
1,808,591; 2,004,193; 2,152,694; 2,852,815; 2,882,560; 3,623,288;
3,437,360; 3,731,445; 4,095,913; 4,471,012; 4,695,502; 4,807,416;
4,953,335; 5,283,102; 5,295,341; 5,437,934; 5,618,602; 5,694,730;
5,736,227; and 4,426,820 and U.S. Published Patent Application Nos.
20020031646 and 20010021431 and U.S. patent application Ser. No.
09/460,928, and all are incorporated in their entirety by reference
herein.
[0068] In one embodiment, a floor panel can have at least two side
edges wherein one side edge has a tongue design and the opposite
side having a groove design, and wherein the tongue and groove are
designed to have a mechanical locking system. These two edges are
preferably the longer of the four side edges. The remaining two
edges, preferably the short joints, can also have a mechanical
locking system, such as the tongue and groove design, or the short
joints can have a standard tongue and groove design, wherein one
edge has a standard tongue design and the other edge has a standard
groove design. The standard design is a design wherein the tongue
and groove is not a mechanical locking system but is generally a
tongue having a straight tongue design in the middle of the edge
and the groove design has the counterpart groove to receive this
tongue. Such a design has many advantages wherein a mechanical
locking system can be used to connect the long sides of the plank,
typically by tilting the tongue into the groove of a previously
laid down plank. Then, the standard tongue and groove design on the
short edges permits the connecting of the short edge of the plank
to the previously laid plank without any tilting motion or lifting
of the previous laid planks. The adhesive can be applied to all
edges or just to the standard tongue and groove edges.
[0069] Thus, the present invention encompasses any type of joint or
connecting system that adjoins edges of floor panels together in
some fashion with the use of straight edges, grooves, channels,
tongues, splines, and other connecting systems. Optionally, the
planks can be joined together wherein at least a portion of the
planks are joined together at least in part by an adhesive. An
example of such a system is described in U.S. patent application
Ser. No. 10/205,408, which is incorporated herein in its
entirety.
[0070] Also, as an option, any edge of the plank can be straight or
bevel. Preferably the edges tapered or beveled so that when two
cores are brought together for attachment, a valley or V-shaped
valley is formed. Preferably, the tapered or beveled edges are at
an angle of from about 5.degree. to about 55.degree., and, more
preferably, at about a 15.degree.-45.degree. angle. Also, the
length of the beveled or tapered edge can be from about 1.0 mm to
about 7.0 mm on each core piece. A preferred design is set forth in
FIG. 3.
[0071] The planks of the present invention can include a top layer
on the core. For example, the top layer can include (a) a high
pressure laminate construction that is comprised of an impregnated
underlayer Kraft paper, a printed decorative layer, and an
impregnated protective overlay compressed together with heat and
pressure to become one single layer; (b) a wood veneer; or (c) a
vulcanized cellulose layer that is made from a number of plies of
paper treated with zinc chloride, an acid to make the surfaces of
the paper gummy and sticky, wherein the gummy plies are then
pressed together. The plank of the present invention does not
require a backing layer, but can optionally have a backing layer.
Preferably, the planks have no backing layer.
[0072] In addition, the decorative element(s) such as wood grains
and/or knots texture can be embossed (e.g., mechanical or chemical
embossing), wherein the design can then be directly printed on the
surface using, for example, a non-contact type digital printing
technology. Another option is to incorporate the pigments into
extrusion operation to create wood grain look on the surface of the
planks by disturbing the material flow in the extruder. The
decorative element can be any design, like natural appearances,
stone, brick, ceramic, wood, marble, and the like or can be other
designs common to or used by the floor industry. The design and
overall upper layers can be textured, such as embossed in register
with the design.
[0073] In one example, the top layer is a laminate on top of the
core; a print layer can be affixed to the top surface of the core,
wherein the print layer has a top surface and a bottom surface. The
print layer, preferably, is an aminoplast resin impregnated printed
paper. Preferably, the print layer has a printed design. The
printed design can be any design which is capable of being printed
onto the print layer. The print layer is also known as a decor
print layer. Generally, the print layer can be prepared by
rotogravure printing techniques or other printing means such as
digital printing. Once a design is printed on the paper, the paper
can then be impregnated with an aminoplast resin or mixtures
thereof. Preferably, the aminoplast resin is a blend of urea
formaldehyde and melamine formaldehyde.
[0074] The print paper, also known as the Deco paper, preferably,
should have the ability to have liquids penetrate the paper such as
a melamine liquid penetrating in about 3 to 4 seconds and also
maintain a wet strength and even fiber orientation to provide good
reinforcement in all directions. Preferably, the resin used for the
impregnation is a mixture of urea formaldehyde and melamine
formaldehyde resins. Urea formaldehyde can contribute to the
cloudiness of the film that is formed and thus is not preferred for
dark colors and the melamine resin imparts transparency, high
hardness, scratch resistance, chemical resistance, and good
formation, but may have high shrinkage values. Combining urea
resins with melamine resins in a mixture or using a double
impregnation (i.e., applying one resin after another sequentially)
provides a positive interaction in controlling shrinkage and
reducing cloudiness. Any type of paper can be used in the present
invention. Preferably, the type of paper used is 80 g/m.sup.2
weight and includes a thickness of 0.16 mm.
[0075] Located optionally on the top surface of the print layer is
an overlay. The overlay which can also be known as the wear layer
is an overlay paper, which upon being affixed onto the print layer,
is clear in appearance.
[0076] The overlay paper is, preferably, a high abrasive overlay
which, preferably, has aluminum oxide embedded in the surface of
the paper. In addition, the paper can be impregnated with an
aminoplast resin just as with the print layer. Various commercial
grades of high abrasive overlays are preferably used such as those
from Mead Specialty Paper with the product numbers TMO 361, 461 (70
g/m.sup.2 premium overlay from Mead), and 561, wherein these
products have a range of Taber values of 4000 to 6000 cycles
according to NALFA Standard LF-01 3.7. Preferably, the type of
paper used is about 46 g/m.sup.2 and has a thickness of about 0.13
mm.
[0077] With respect to the print layer and the overlay, any amount
of aminoplast can be used. Preferably, the amount of aminoplast
resin is from about 60 to about 140 g/m.sup.2 and, more preferably,
from about 100 to about 120 g/m.sup.2.
[0078] A multilayered overlay can be used to provide printed
decoration and protection for the product. This overlay can have a
printed paper as a decorative layer. On the top surface of the
printed paper can be a layer of urethane acrylate containing
aluminum oxide for enhanced abrasion resistance. Above this layer
can be another layer of urethane acrylate without aluminum oxide
for improved surface visuals. Below the print layer can be a primer
to enhance the bond to the base core material. The multilayered
overlay can be produced by building layers of the primer liquid,
and the two acrylic layers as liquid onto the print layer and then
e-beam curing to produce the solid cured product.
[0079] As an option, an underlay can be located and affixed between
the bottom surface of the print layer and the top surface of the
core. Preferably, the underlay is present and is paper impregnated
with an aminoplast resin as described above with respect to the
print layer and overlay. Preferably, the underlay is Kraft paper
impregnated with aminoplast resins or phenolics and, more
preferably, phenolic formaldehyde resin or melamine formaldehyde
resin which is present in an amount of from about 60 g/m.sup.2 to
about 145 g/m.sup.2 and, more preferably, from about 100 g/m.sup.2
to about 120 g/m.sup.2 paper. Any type of paper can be used.
Preferably, the type of paper used is about 145 g/m.sup.2 and
includes a thickness of about 0.25 mm. The underlay is especially
preferred when extra impact strength resistance is required.
[0080] Other types of layers, which can be used in the present
invention, such as wood veneer and vulcanized cellulose layers, can
include the same components described above with respect to the
laminate. Wood veneers used as the top layer can be any type of
species such as oak, maple, cherry, hickory, beech, pine, walnut,
mahogany, chestnut, and teak and the like. The thickness of the
veneer can be in the range of 0.005 inch to 0.250 inch. Preferably,
the thickness of the veneer is in the ranges of 0.080 inches to
0.160 inches. The veneer on the top can be decorated with a printed
design to highlight the grains or knots or to mimic certain wood
species or to emboss the surface to create vintage appearance and
the like.
[0081] As a protective layer, a radiation curing or e-beam curing
urethane acrylate coating(s) can be applied on the surface of any
previous layer or on the core upper surface to provide the required
surface properties such as scratch and wear resistance, scuff
resistance, stain and chemical resistance and the foremost
importance is the appearance retention. The coating(s) can
incorporate the abrasive resistance particles in the urethane for
better surface protection that typically has abrasion level of
300-500 cycles per NALFA test.
[0082] While the core can be made in a number of ways, preferably,
the core is formed by an extrusion process wherein the polymeric
material, natural fiber, along with any other optional ingredients
are blended together and are then fed into an extruder by a feeder,
wherein the extruder, preferably, uniformly mixes the polymeric
material with the natural fiber and the application of heat and
auger action can melt the polymeric material to the extent that it
is eventually fed through a die, wherein the die can be in the
shape of the core. Preferably, the fiber or flour is uniformly
distributed and encapsulated throughout the polymeric material.
Preferably, the fiber or flour is substantially encapsulated or
coated individually by the polymeric material when formed into the
core.
[0083] In forming the core of the present invention, the
ingredients making up the formulation can be mixed prior to
introducing the ingredients into an extruder or can be mixed by way
of the extruder.
[0084] In making the planks of the present invention, the starting
polymer, which is preferably a thermoplastic, can typically, be in
the form of a powder that is mixed with the natural fibers inside
the extruder without going through the pre-mixing process.
[0085] As an alternative, the ingredients, including the starting
polymer(s), and the natural fiber/flour can be intimately mixed
together under heat and/or pressure to first form pellets of the
material. These pellets can then be introduced into an extruder for
formation of the desired shape of the core. The pellets can have
any size suitable for use in an extruder.
[0086] The natural fibers can be reduced to the desired particle
size by any reducing technique, such as using a pulverizer, mill,
and the like. In addition, to obtain the desired moisture content
in the natural fibers, any drying technique can be utilized such as
conductive, convective, and radiation heating means.
[0087] In more detail, the extrusion process permits a) an
economically feasible design by designing a profile with cavities
inside the structure and b) a highly versatile method of achieving
the complicated profile design of the preferred plank in
conjunction with additional machining afterwards for the tongue and
groove, for instance. Generally, the extruder can be designed to
uniformly mix the various ingredients together to extrude, using a
die, in the form of a core. While any extruder can be used which
can extrude the desired design of the plank for polymeric and
natural fiber materials, preferably, the extruder is a twin screw
extruder, such as one from American Maplan Corporation, such as
model TS-88 or TS-110. The TS-88 includes the ability to process
polymeric profiles with a maximum output capacity of about 900
lb/hr, based upon a compound bulk density of 37 lb/ft.sup.3. The
TS-88 is a twin screw extruder which includes a barrel heating
section and a cooling section as well as a vacuum system. In the
extruder, there can be 12 temperature zones with 6 for cooling and
a temperature control system.
[0088] Preferably, the plank can be prepared by extruding the core
as described above and forming a top layer, such as a wood veneer
or laminate or vulcanized cellulose layer. The laminate can
comprise the overlay affixed to the top surface of the print layer
and, optionally, the underlay layer which is affixed to the bottom
surface of the print layer. In one example, wherein the top layer
is a laminate, the laminate can be prepared by, for instance, any
process customarily used to manufacture laminate films such as a
continuous double belt press. In general, if an underlay is used,
the phenolic impregnated kraft backer, the print layer and the
overlay can be fed into a continuous double belt press that serves
as a laminating calendar. Preferably, the continuous operation is
an isobaric system wherein pressures can go as high as 30 bars and
the line speed can be up to 20 meters per minute. The pressure zone
length is about 2 to 3 meters. In this continuous double belt press
system, the isobaric system provides a steady uniform pressure
effect on each point of the treated surface of the laminate.
Embossing of the laminate can be accomplished by embossed release
paper or the belt of the double belt press can be embossed to
produce surface textures. In a continuous double belt press, the
simultaneous heating of the laminate with proper dwell time and
pressure forms the laminate film which then can be rolled up for
subsequent application. Once the laminate is formed it can be
applied onto the core and is preferably affixed by any means, such
as with an adhesive. Preferably the adhesive is a hot melt adhesive
such as hot melt glue like hot melt polyurethane glue.
[0089] The hot melt adhesive, such as the hot melt polyurethane
adhesive, is, preferably, applied to the back surface of the
laminate film at a preferred temperature of from about 250.degree.
F. to about 300.degree. F., more preferably, from about 250.degree.
F. to about 275.degree. F. These temperatures may vary slightly
depending upon the adhesive. The application of the hot melt
adhesive to the laminate can be done by a direct roll coater. The
laminate with the adhesive on the back surface can then be heated
to an adequate temperature to soften the laminate and allow the
laminate to form to the profile of the thermoplastic core and thus
be affixed permanently. The typical wrapping machine is designed to
hold the laminate to the contour of the thermoplastic plank as it
is being cooled to below about 90.degree. F. to about 100.degree.
F. The thickness of the application of the adhesive can have an
effect on the impact resistance of the finish product. If the
application of the adhesive is too thick, an impact may cause the
laminate to become brittle and crack. A thin application enables
the laminate to flex less during impact and minimize the damage.
Application of the adhesive is preferably from about 5 to about 15
g/ft.sup.2 and more preferably from about 6 to about 12 g/ft.sup.2.
A preferred hot melt adhesive is Ever-Lock.RTM. 2U145/2U230
modified polyurethane adhesive reactive hot melt from Reinhold
Chemicals, Inc.
[0090] Wood veneer and vulcanized cellulose can be laminated in a
similar manner. These products may be provided as coils or as
individual strips. In either case, the hot melt adhesive which is
heated to the temperatures described above can be applied to the
back of the overlay material to be laminated onto the base plank.
The overlay with adhesive is then mated to the base plank under
heat and the pressure of multiple rollers. The heat used needs to
be sufficient to re-soften the hot melt and if necessary to soften
the overlay until it bends and conforms to the surface onto which
it is being laminated. In the case of certain laminate overlay
products to bend the overlay around a bevel edge, the temperature
may need to be 300-320 degrees F. If no bending is needed, and
re-softening the adhesive will suffice, the temperature can be
lower, preferably to 230-260 degrees F. The cooling process begins
until at the end of the line the temperature of the product is
between about 90-100.degree. F.
[0091] As described above, the various planks of the present
invention can be connected together by a tongue and groove system
with a mechanical locking profile, or using full spread adhesive to
glue the planks together or using spline or snap connector. A
separate spline or snap connector is a separate piece and is
especially effective when a groove is present on two, opposite
sides or edges of the plank. The snap or tongue piece can be
inserted into one groove and is long enough to extend outside the
groove and fit into a respective groove of another plank in order
to connect the two pieces together. The tongue piece or snap
connector can be a co-extruded material whose core is made of a
rigid thermoplastic material such as polyvinyl chloride and whose
outer co-extruded top and bottom shell is made of a soft
thermoplastic material such as plasticized polyvinyl chloride or
polyvinyl chloride/rubber blends. The hard inner core allows some
rigidity for positioning and installation ease. The soft outer
shell on top and bottom surface allow compressibility for easy fit
into the plank groove. In addition, due to topographical features
such as teeth on the spline, an improved grab onto the teeth of the
plank groove can be obtained. In another example, the tongue piece
or snap connector can be a co-extruded material that is made of at
least one polymeric material and at least one natural fiber.
[0092] In the present invention, while each of the planks can be
affixed to the sub-floor or substrate, it is preferred that the
planks be attached only to each other through a connector system
such that there is a floating floor system. This promotes fast and
easy laying of the floor system.
[0093] With the planks of the present invention, the present
invention achieves many benefits and advantages such as low cost,
moisture resistance and mechanical properties such as impact
strength, resistance to indentation and gouges, and beneficial
acoustical properties. Further, the laminate plank system of the
present invention can be used in any environment, dry, wet, indoor,
or outdoor, since it is not susceptible to moisture. In an
embodiment of the present invention, the planks are less sensitive
to the combined effects of temperature and humidity than is the
standard laminate product. As a result, the need for T-moldings to
act as expansion and contraction areas of the floor can generally
be eliminated. These T-moldings are not only unsightly, but can act
as tripping hazards. By the elimination of T-moldings/expansion
joints in the walkway, the present invention allows the use of the
floor in commercial applications. In an embodiment, the present
invention expanded only one fifth as much as a standard laminate
product under identical conditions. These conditions take the
product from ambient room conditions to conditions of 90% relative
humidity and 90.degree. F. Standard expansion joints for laminates
are typically placed every 30 feet. Thus, a hallway of 150 feet
would be feasible without an expansion joint with the present
invention.
[0094] In the preferred embodiment of the present invention, the
installation method utilizes the unique design of the product to
eliminate the need for glue used in tongue and groove
connections.
[0095] Furthermore, the installer has options for installing the
plank product. In one method, a floating floor installation method
can be utilized with a floating floor, applying glue to a tongue
and groove joining system can be used. Such glues as waterborne
polyvinyl acetate, two part epoxy or urethane systems or one part
moisture cure polyurethane adhesive can be used. In this method, no
adhesive is applied to bond the product to the subfloor surface.
The benefits of this method have been described earlier.
[0096] In a second method, a full-spread adhesive is applied
between the underside of the product and the sub-floor surface.
This provides the advantages of added dimensional stabilization and
sound deadening. Both of these properties would be beneficial in
commercial applications. Glues that can be used include reactive
type systems such as moisture cure urethanes or two part epoxies or
urethanes.
[0097] In a third method, a click mechanical locking system can
also be possible.
[0098] In a fourth method, the combination of a mechanical lock
system with adhesive together can be an option as well.
[0099] In addition, the excellent moisture resistance and sound
deadening qualities of this product can eliminate the need for
underpadding, though use of underpadding is an option.
[0100] A further embodiment of the present invention relates to a
plank which comprises the same plank described above but, in lieu
of a top layer on top of the plank, a design is printed directly on
the top surface of the plank using any number of printing
techniques such as gravure printing, transfer printing, digital
printing, flexo printing, and the like. Or, a printed thermoplastic
film (e.g., PVC) or a wood veneer and the like can be laminated to
a thermoplastic plank. A protective coating can then be placed on
top of the printed design. Any type of protective coating or wear
layer can be used, such as a polyurethane type coating with or
without wear resistant particles in the coating. Thus, a plank
would have a core, where the core has a top surface and bottom
surface as well as opposing sides and a printed design directly on
the top surface of the plank and optionally at least one protective
coating on top of the printed design. The top surface of the plank
as described earlier can have a textured surface as described
above.
[0101] This type of plank can be made by extruding at least one
polymeric material and at least one natural fiber into the shape of
the core and then printing a design directly on the top surface of
the plank and then, optionally, applying at least one protective
coating on top of the printed design and curing the protective
coating. The protective coating can be applied by conventional
techniques, such as with a curtain coater, direct roll coater,
vacuum coater, differential roll coater, air knife coater, or spray
apparatus.
[0102] In another embodiment of the present invention, a plank for
surface coverings, such as flooring, has a core and an extruded
layer on the top surface of the core, wherein the extruded layer
includes at least one thermoplastic material with one or more
pigmented compounds. The extruded layer on top of the extruded core
can simulate various designs such as wood grain and the like.
[0103] The plank in this embodiment can be made by co-extrusion
techniques which involve extruding the core and extruding either
simultaneously or subsequently a layer containing at least one
thermoplastic material with one or more pigmented compounds on top
of the extruded core.
[0104] Another embodiment involves a plank having the same design
as described above with a printed polymeric film, such as a PVC
film placed on the top surface of the extruded core. The printed
polymeric film can be a polymeric film having a printed design on
the film wherein the film would preferably be from about 10 to
about 20 mil thick. One or more wear layers or protective coatings
can be placed on top of the printed polymeric film. The polymeric
film can be placed on top of the extruded core by typical
lamination techniques, such as heating the printed film, then
pressing the film to the extruded core to bond them together, or
using glue to bond them together.
[0105] With reference to the Figures, the Figures show various
aspects of several embodiments of the present invention. For
instance, FIG. 1 represents a schematic diagram of a side view of
one embodiment of the plank. The particular Figure is with the
prospective view of looking at the front edge of the plastic wood
composite plank wherein the groove (76) would run along each edge
of the plank. The spline or tongue (64) is inserted along the
length of each groove (76). Indicia (72) points to the edges of the
spline having the groove whereas the indicia (68) points to the
lower or bottom surface of the spline and the indicia (70) points
to the top surface or the surface that typically, but optionally,
receives the print layer and the like. As illustrated, the feet or
strips (62) of post-extruded material extend along the bottom
surface of the core from the front edge to the back edge. As can be
seen in FIG. 1, typically these post extruded lines of material act
as a support mechanism and typically run parallel in the same
parallel direction as the cavities (60). Preferably, and as shown
in the exemplary embodiments in FIG. 1, the side of the plank which
has a groove is typically tapered or beveled and is shown by
indicia (78).
[0106] FIG. 2 is an exemplary representation of one type of spline
or tongue (64) that can be used in one embodiment of the present
invention. As can be seen in FIG. 2, the preferably soft material
(82), such as plasticized PVC, is located on the top and bottom
surface of the spline or tongue in order to ensure a tighter fit
with the groove of the plank. The spline can be made of the same
material as the core such as PVC, or the spline can be made of a
different material. The spline design, preferably, includes a
thickness of from about 3 mils to 5 mils thicker than the groove of
the plank (for a solid spline design). The spline will have a
thickness of from about 24 mils to 42 mils thicker than the groove
in the plank for the double tooth (top and bottom) design. If the
spline is too thick, it can open the groove and cause edge peaking.
If the spline is too thin, it does not effectively engage the
groups with the teeth in the groove. The edges of the spline or
tongue (64) are tapered or beveled (80) in order to ensure that the
tongue can be inserted into the groove.
[0107] FIG. 3 makes a reference to a spline (64) which includes
teeth (90) on the surfaces which engage the groove (76) of the
plank. Further, as can be seen in FIG. 3, the top surfaces of the
plank form a V shape valley (88) and the edge of the plank touches
each other whereas the bottom portions of each respective plank are
cut in order to have a slightly shorter length in order to form a
gap (86) which ensures that the top ends (88) touch each other and
do not leave any gaps on the walking surface of the planks. The top
layer(s) (84) can be a print layer and the like.
[0108] Referring to FIG. 4, FIG. 4 is a depiction of a tongue (76)
which has receiving teeth (92) for a spline or tongue of the design
shown in FIG. 3 (90). FIG. 4 further shows the post extruded lines
on the bottom surface of the extrusion plank (62) as well as the
various angles and cuts of the cavity (60) as well as the receiving
groove (76). Further, the beveled or tapered edge (78) is shown in
FIG. 4.
[0109] Referring to FIG. 5, a flat spline without co-extrusion top
and bottom surface can be inserted into groove and bonded with
waterborne adhesive such as polyvinyl acetate as the glue.
[0110] Furthermore, a regular tongue and groove configuration used
on most of the engineered wood flooring or solid wood flooring, or
click joint systems that are widely used as a connection system for
laminate flooring can also be possible to join the planks together
with or without a waterborne adhesive.
[0111] Furthermore, it is also possible to weld the joint together
by an ultrasonic welding machine in a tongue and groove
configuration.
[0112] The planks of the present invention can be used in a variety
of applications including, but not limited to, wall panels, ceiling
panels, flooring surfaces, decks, patios, furniture surfaces,
shelving, and other surface coverings or parts thereof.
[0113] The present invention will be further clarified by the
following examples, which are intended to be purely exemplary of
the present invention.
EXAMPLES
Example 1
Laminated Overlay (T-11) on Wood Composite Base with a Hot Melt
Polyurethane Adhesive.
[0114] The laminated overlay layer utilized included a top layer
that was 0.004 inches thick and was composed of a cross-linked
melamine-impregnated paper containing aluminum oxide. The top layer
was designed to be clear and to protect the decorative print layer
below it. The second layer, which was located under the top layer,
was a gravure-printed paper for decorative purposes. The third
layer (bottom layer), which was located under the second layer, was
composed of cross-linked phenolic impregnated Kraft paper. The
purpose for the bottom layer was to provide support and stability
for the top two layers during processing.
[0115] The three layers that made the laminated overlay were
consolidated under heat and pressure in a continuous consolidation
procedure performed on a Grecon unit.
Section A
[0116] The core of the plank was extruded wood fiber composite
having the following formulation: TABLE-US-00005 Maple Wood Fibers
55% by wt. Exxon Mobile Polyethylene LB 0100-00 40% by wt.
Polyester lubricant (Struktol TPW 104) 5% by wt.
[0117] A small amount (less than or equal to 1%) of color
concentrate was included to tint the base extrusion. The mesh size
distribution of the maple wood fibers was as follows:
TABLE-US-00006 Mesh Size Particle Size (inch) % by wt. Retained on
Mesh 30 0.023 30 40 0.016 30 60 0.0098 30 <60 fines 10
[0118] The extrusion was performed using an American Maplan
(division of Battenfeld International) TS-110 counter-rotating twin
screw extruder. The zone temperatures as well as the monitored
temperature and pressure readings were recorded and are listed
below in Table I. TABLE-US-00007 TABLE I Extruder Conditions
Measurement Description Measured Value Zone Temperatures Zone 1
399.7.degree. F. Zone 2 384.7.degree. F. Zone 3 350.0.degree. F.
Zone 4 350.0.degree. F. Zone 5 299.9.degree. F. Melt Temperature
380.4.degree. F. (between Zone 5 and die) Melt Pressure 2176.5 psi
(between Zone 5 and die) Main Motor rpm 944.5 Main Motor % load 54%
Screw Oil Temp 300.degree. F. Screw Oil Core 326.4.degree. F.
[0119] The extruder included a five-inch wide rectangular shaped
profile with a thickness of 0.345+/-0.003 inches.
Section B
[0120] The laminate overlay was adhered to the core by a hot melt
cross-linked polyurethane adhesive. In particular, the adhesive was
Forbo (Reichhold) 2U-316. This adhesive was heated to 250.degree.
F. and applied to the phenolic back of the three-layered laminate
which was slightly preheated to 135.degree. F.
[0121] The laminate was then joined to the core. This was then
briefly heated to 250-270.degree. F. for re-softening the adhesive.
Immediately after the softening heat was applied, a roller pressed
the laminate firmly onto the core. The product was then cooled with
water to below 90.degree. F.
[0122] In the rectangular construction with a flat top, high heat
in excess of 310.degree. F. was not used because the laminate
overlay was not shaped to include a beveled edge, for example. The
application of higher heat to the edge may be useful if the
laminate overlay needs to be softened and shaped around a bend or
bend portion of the profile.
[0123] When heat is applied to the top of the product or the top
layer of the product (top heat), a sufficient amount of heat is
also, preferably, applied to the bottom of the product (back heat)
to bring the product into a thermally balanced state. The amount of
back heat applied, generally, depends on the moisture content of
the T-11 three-layered laminate, the product stiffness, and the
weight of the base plank. The preferred moisture contents of
overlay as measured by weight loss for 24 hours at 162.degree. F.
is 3%-4%. If the T-11 laminate overlay contains 3.5 wt % moisture,
a plank should be set with a positive dome of 250-300 mils over six
feet for being able to remain its flatness in variable
environments.
Example 2
Wood Veneer Overlay on Wood Composite Base
[0124] The core was prepared as described above in Example 1,
Section A, using the TS-110 extruder from American Maplan Company.
However, the decorative element adhered to the top of the core was
an actual wood veneer. The wood veneer included polyester back with
a thin (0.006 inches thickness) red oak veneer adhered to the top
of the polyester. The polyester was used to hold the thin veneer to
be processed as a continuous coil when it was wrapped onto the
extruded wood composite base. The veneer overlay was adhered to the
wood composite base with a hot melt polyurethane adhesive Forbo
(Reichhold) 2U-316.
[0125] The temperature and other conditions at which the veneer was
wrapped and the method of laminating the veneer to the wood
composite were the same as the conditions and method described in
Example 1, Section B, with the exception that cooling water was not
in contact with the face of the wood veneer.
[0126] To protect the red oak veneer from wear and tear, various
fillers, sealers, and a polyurethane liquid layer, all of which
were properly cured, were applied to the red oak veneer on the
process line.
[0127] The steps and materials used in this processing were as
follows: TABLE-US-00008 Process Step Materials Quantity Applied
Stain UV Curable Auburn Tint 0.21 g/36 in.sup.2 Denib Filler-1
Filler 0.50 g/36 in.sup.2 Denib Filler-2 Filler 0.20 g/36 in.sup.2
Denib Sealer (standard)-1 Standard Sealer 0.45 g/36 in.sup.2 Alox
Sealer Sealer with Alum Oxide 0.40 g/36 in.sup.2 Denib Standard
Sealer-2 Standard Sealer 0.45 g/36 in.sup.2 Topcoat wet on wet High
Gloss UV Curable 0.31 g/36 in.sup.2 (50 gloss coating)
[0128] The stain used to tint the red oak veneer was the auburn
tint stain. All the process steps described above were in a
continuous line. The line gradually increased speed to eliminate
any back-up and congestion problems. All of the application heads
in the process were roll applicators. After the UV curable stain
weight was applied and cured, the plank traveled under denibbing
rolls, wherein the raised grains in the staining process were
removed.
[0129] Next, a clear UV curable filler was applied and cured. The
plank was again denibbed, followed by a second filler application
weight and denibbing.
[0130] A clear UV curable sealer weight and a curing agent were
applied to the plank using an application head. This was followed
by applying a UV curable aluminum oxide sealer and curing the
sealer. The plank was then denibbed and a standard UV curable
sealer weight was applied and cured. Finally, two wet applications
of the 50 gloss Valspar UV curable coating were applied, weighted,
and cured.
Example 3
Vulcanized Cellulose on Wood Composite Base
[0131] The core was prepared as described above in Example 1,
Section A, using the TS-110 extruder from American Maplan Company.
However, the decorative element adhered to the top of the plank was
a vulcanized cellulose layer with a printed wood grain design. The
vulcanized cellulose layer was supplied by NVF Company and is known
as Yorkite Vulcanized Fiber (YVF). The vulcanized cellulose layer
was prepared by soaking cellulose fibers in CaCl2. The fibers were
then compacted and heated to form a cross-linked cellulosic layer.
The vulcanized cellulose layer used in this example was 0.020
inches thick.
[0132] The YVF overlay was adhered to the wood composite base with
a hot melt polyurethane adhesive, such as Forbo/Swift 20-316. The
temperature and other conditions at which the YVF was wrapped and
the method of laminating of the YVF to the wood composite base were
the same as the conditions and method described in Example 1, with
the exception that cooling water was not in contact with the face
of the wood veneer. The YVF was also protected from wear by a
coating. To protect the YVF, a UV curable coating or a
melamine-impregnated overlay was applied to the YVF before YVF was
laminated to the wood composite base.
Example 4
[0133] A pelletized blend of HDPE, pine wood fibers, and coupling
agents was added with a lubricant at the extruder such that the
final formulation was: TABLE-US-00009 (wt %) Wood Fiber 70% HDPE 22
Coupling Agent 2 Lubricant 6
[0134] This was extruded on an American Maplan TS 110 twin screw
extruder into a rectangular plank 5 inches wide and 0.340 inches
thick. Zone temperatures were set 320 F.-330 F., die set at 410-420
F., Melt temp=350-355 F.
[0135] The plank was tested for percent thickness swell when
submersed in water for 24 hours yielding a value of 2.8+/-0.5%. The
plank had a static load indent of 0.0005+/-0.0001 inch. The static
load indentation test was run by placing 1160 psi pressure on the
product for 24 hours, removing the pressure, allowing rebound for
24 hours and then measuring indent.
Example 5
[0136] A blend of purchased maple wood fibers 30-60 mesh size was
mixed with HDPE and agglomerated into pellets on a Pallmann
Palltruder.RTM.. The weight ratio of wood fibers to HDPE was 1.4:1.
These pellets were extruded with lubricant added at the extruder.
The extruder used was an American Maplan TS 110 twin screw extruder
and the pellets were extruded into planks of dimensions described
in Example 4. The extruder temperatures were similar to those in
Example 4.
[0137] The final extruded formulation was TABLE-US-00010 Wt % Wood
fiber 54% Exxon Mobil EA 55-003 (HDPE) 42 Lubricant 4
[0138] The plank was tested for water swell and static load
indentation as described in Example 4. The values measured were: 24
hour water thickness swell was 3.7+/-0.5%. Static load 1160 psi was
0.0014+/-0.0003 inch.
Example 6
[0139] Wood fibers were produced by size reduction of wood waste
from wood floor fininshing operation. The fibers were hammermilled
and classified so that the 20/50 mesh screen size was retained.
This produced particles having a size of 0.8 mm to 0.3 mm. These
were agglomerated into a pellet using the Palltruder.RTM. in a
blend of wood fibers to HDPE at a weight ratio of 1.4:1.
[0140] These pellets were extruded with lubricant added at the
extruder. The extruder used was an American Maplan TS 110 twin
screw extruder into planks of dimensions described in Example 4.
The extruder temperatures were similar to those in Example 4.
[0141] The final extruded formulation was TABLE-US-00011 Wt % Wood
fiber 54% Equistar AD 60-007 HDPE 42 Lubricant 4
[0142] The plank was tested for water swell and static load
indentation as described in Example 4. The values measured were: 24
hour water thickness swell was 3.1+/-0.4%. Static load 1160 psi was
0.0012+/-0.0006 inch.
Example 7
[0143] A blend of purchased maple wood fibers 30-60 mesh size was
extruded directly with HDPE and lubricant on an American Maplan TS
110 twin screw extruder into planks of dimensions described in
Example 4. The extruder temperatures were similar to those in
Example 4.
[0144] The final extruded formulation was TABLE-US-00012 Wt % Wood
fiber 54% Exxon Mobil EA 55-003 (HDPE) 42 Lubricant 4
[0145] The plank was tested for water swell and static load
indentation as described in Example 4. The values measured were: 24
hour water thickness swell was 4.4+/-0.8%. Static load 1160 psi was
0.0010+/-0.0005 inch.
Example 8
[0146] Wood composite planks with Elesgo 350 gram overlay and T-11
Overlay were prepared by adhering the respective overlays to a wood
composite planks comprised of 55 wt % maple wood fibers, 40 wt %
HDPE resin and 5 wt % lubricant. [0147] Bow--refers to vertical
movement of plank ends in relation to the plank center down the
length of the plank. [0148] A position where the ends are above the
center is called "horns up" or positive bow. [0149] A position
where the center is above the ends is called horns down or negative
bow. This may also be referred to as dome. [0150] Cup--refers to
vertical movement across the plank. Where the sides are above the
center in the z-direction, the cup is called positive cup. Where
the center is above the sides is called negative cup.
[0151] The negative bow (dome) was induced by setting an infrared
heater at 1000 degrees F. set point. Actual thermocouple
temperature in the infrared oven was 815 degree F. The planks were
run under the heater with the bottom side of the plank facing the
heater. The speed of the sample under the oven and distance from
the IR heater to the back of the plank were varied. The speed was
varied between 5 and 9 feet per minute and distances were varied
between 6 and 9 inches. Raytek temperature measurements were taken
as the sample exited from the oven. Essentially, back heat
temperatures in the 300-500.degree. F. range can induce a negative
bow (dome) of 1 to 11/8 inch.
[0152] Applicants specifically incorporate the entire contents of
all cited references in this disclosure. Further, when an amount,
concentration, or other value or parameter is given as either a
range, preferred range, or a list of upper preferable values and
lower preferable values, this is to be understood as specifically
disclosing all ranges formed from any pair of any upper range limit
or preferred value and any lower range limit or preferred value,
regardless of whether ranges are separately disclosed. Where a
range of numerical values is recited herein, unless otherwise
stated, the range is intended to include the endpoints thereof, and
all integers and fractions within the range. It is not intended
that the scope of the invention be limited to the specific values
recited when defining a range.
[0153] Other embodiments of the present invention will be apparent
to those skilled in the art from consideration of the specification
and practice of the present invention disclosed herein. It is
intended that the specification and examples be considered as
exemplary only, with the true scope and spirit of the present
invention being indicated by the following claims and equivalents
thereof.
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