U.S. patent application number 11/065787 was filed with the patent office on 2005-08-04 for method and apparatus for forming composite material and composite material therefrom.
This patent application is currently assigned to PSI International Inc.. Invention is credited to Maine, Francis William, Newson, William Roy.
Application Number | 20050171246 11/065787 |
Document ID | / |
Family ID | 22628332 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050171246 |
Kind Code |
A1 |
Maine, Francis William ; et
al. |
August 4, 2005 |
Method and apparatus for forming composite material and composite
material therefrom
Abstract
A system and method for extruding composite material and the
composite material therefrom. The composite material consists of a
filler mixed with a binding agent. The composite material is
extruded as billets with enhanced physical properties, such as
colour, texture, electrical conductivity and fire retardancy, and
contains a dispersion pattern of the filler material. A system and
method are also provided for drawing the composite material through
a die and a composite material produced thereby. The drawn
composite material exhibits a density reduction over the density of
the starting material and enhanced physical properties. A
particularly useful tongue and groove arrangement are also provided
for joining adjacent strips of a composite material made according
to the extrusion process.
Inventors: |
Maine, Francis William;
(Ontario, CA) ; Newson, William Roy; (Ontario,
CA) |
Correspondence
Address: |
PEARNE & GORDON LLP
1801 EAST 9TH STREET
SUITE 1200
CLEVELAND
OH
44114-3108
US
|
Assignee: |
PSI International Inc.
|
Family ID: |
22628332 |
Appl. No.: |
11/065787 |
Filed: |
February 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11065787 |
Feb 25, 2005 |
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10168716 |
Oct 28, 2002 |
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10168716 |
Oct 28, 2002 |
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PCT/CA00/01555 |
Dec 19, 2000 |
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60172586 |
Dec 20, 1999 |
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Current U.S.
Class: |
524/13 ; 524/27;
524/449; 524/451; 524/543 |
Current CPC
Class: |
B29C 48/08 20190201;
B29C 48/9135 20190201; E04F 15/10 20130101; B29C 48/475 20190201;
B29K 2711/14 20130101; B29C 48/07 20190201; Y10T 428/24777
20150115; Y10T 428/195 20150115; B29C 48/865 20190201; B29C 48/90
20190201; B29C 48/904 20190201; B29K 2105/16 20130101; B27N 3/28
20130101; E04F 2201/0153 20130101; B29C 55/30 20130101 |
Class at
Publication: |
524/013 ;
524/027; 524/449; 524/451; 524/543 |
International
Class: |
C08J 003/00 |
Claims
What is claimed is:
1. A composite material comprising: an oriented polymer; and a
particulate filler dispersed throughout said oriented polymer,
wherein said composite material has a reduced density which is less
than the combined masses of the oriented polymer and particulate
filler divided by their combined respective volumes.
2. The composite material of claim 1 wherein: said oriented polymer
is a plastic; and said particulate filler is selected from the
group consisting of wood, slate, talc, vermiculite and mica.
3. The composite material of claim 2 wherein: said oriented polymer
is selected from the group consisting of polypropylene,
polyethylene and polyvinyl chloride.
4. The composite material of claim 1 where: said oriented polymer
is present in an amount of from 95 to 60 percent by weight as
compared to said particulate filler.
5. The composite material of claim 4 wherein: said oriented polymer
is selected from the group consisting of polypropylene,
polyethylene, and polyvinyl chloride.
6. The composite material of claim 4 wherein: said particulate
filler is selected from the group consisting of wood, slate, talc,
vermiculite and mica.
7. The composite material of claim 4 wherein: said oriented polymer
is polypropylene; and said particulate filler is wood sawdust.
8. The composite material of claim 7 wherein: said sawdust has a
particle size of about 60 mesh.
9. The composite material of claim 8 wherein: said particulate
filler is present in an amount of from 20% to 30% by weight as
compared to said oriented polymer.
20. An oriented composite material as produced by a process
comprising the steps of: i) combining an extrudable polymer with a
cellulose based particulate filler to form a starting material; ii)
heating and extruding said starting material into a first column;
iii) adjusting the temperature of said first column to a drawing
temperature; iv) presenting said first column to a drawing die and
causing said first column to exit said drawing die in a second
column having a cross-sectional area less than that of said first
column; v) applying a pulling force to said second column to draw
said first column through said drawing die at a rate sufficient to
cause orientation of said polymer and to cause said second column
to diminish in density to form said composite material.
21. A composite material comprising: a filler for enhancing the
physical properties of said composite material; and a binding
agent, mixed with said filler, for permitting extrusion of billet
of said composite material in a plastic extrusion process to
provide a predetermined dispersion pattern of said filler in said
composite material.
22. The composite material of claim 21 wherein said filler is a
natural fiber.
23. The composite material of claim 21 wherein said filler is a
synthetic fiber.
24. The composite material of claim 21 wherein said binding agent
is a polymer.
25. A composite material comprising a particulate material
dispersed in an oriented polymer.
26. The composite material of claim 25 wherein said particulate
material is wood sawdust having a particle size of about 60 mesh;
said oriented polymer is polyethylene; and said oriented polymer
forms from 60% to 95% by weight of said composite material.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to extrusion processes. In
particular, the present invention relates to an extrusion method
and apparatus for composite material.
BACKGROUND OF THE INVENTION
[0002] The process of solid-state extrusion is known. Extrusion
processes that are used include ram extrusion and hydrostatic
extrusion. Ram extrusion utilises a chamber in which polymer
billets are placed, one end of which contains a die and the other
an axially mobile ram. The billet is placed within the chamber such
that the sides of the billet are touching the sides of the chamber.
The mobile ram pushes the billets and forces them through the
die.
[0003] In hydrostatic extrusion processes, the billet is of a
smaller size than the chamber and does not come into contact with
the sides of the chamber. The chamber contains a pressure
generating device at one end and a die at the other. The space
between the billet and the chamber is filled with a hydraulic
fluid, pumped into the chamber at the end containing the pressure
generating device. During operation pressure is increased on the
hydraulic fluid and this in turn transmits pressure to the surface
of the billet. As the billet passes through the die some of the
hydraulic fluid adheres to the surface of the billet, providing
additional lubrication to the process.
[0004] Both processes produce a polymer that is oriented in a
longitudinal direction, having increased mechanical properties,
such as tensile strength and stiffness. However, the orientation in
a longitudinal direction can also make the polymer weak and subject
to transverse cracking or fibrillation under abrasion. The process
of pushing the polymer through a die can also create surface
imperfections caused by frictional forces.
[0005] U.S. Pat. No. 5,204,045 to Courval et al. discloses a
process for extruding polymer shapes with smooth, unbroken
surfaces. The process includes heating the polymer shape to below
the melting point of the polymer and then extruding the polymer
through a die that is heated to a temperature at least as high as
the temperature of the polymer. The process also involves melting a
thin surface layer of the polymer to form a thin, smooth surface
layer. The process produces a material of a uniform appearance and
subsequent commercial applications are limited as a result.
SUMMARY OF THE INVENTION
[0006] A composite material comprising an oriented polymer and a
particulate filler dispersed throughout the oriented polymer. The
composite material has a reduced density which is less than the
combined masses of the oriented polymer and a particulate filler
divided by their combined respective volumes.
[0007] The oriented polymer maybe of plastic and the particulate
filler may be selected from the group consisting of wood, slate,
talc, vermiculite and mica.
[0008] The plastic may be polypropylene, polyethylene and polyvinyl
chloride and present in an amount of from 95% to 60% by weight as
compared to the particulate filler.
[0009] According to one embodiment, the oriented polymer is
polypropylene and the particulate filler is wood sawdust having a
particle size of about 60 mesh and present in amount of from 20% to
30% by weight as compared to the weight of the oriented
polymer.
[0010] A process for producing an oriented composite material, said
process comprising the steps
[0011] of combining:
[0012] (i) an extrudable polymer with a particulate filler to form
a starting material;
[0013] (ii) heating and extruding said starting material into a
first column;
[0014] (iii) adjusting the temperature of said first column to a
drawing temperature;
[0015] (iv) presenting said first column to a drawing die and
causing said first column to exit said drawing die in a second
column having a cross-sectional area less than that of said first
column;
[0016] (v) applying a pulling force to said second column to draw
said first column through said drawing die at a rate sufficient to
cause orientation of said polymer and to cause said second column
diminish in density to form said composite material.
[0017] The extrudable polymer may be of plastic, such as
polypropylene, polyethylene or polyvinyl chloride.
[0018] The particulate filler may be wood, slate, talc, vermiculite
or mica.
[0019] The extruable polymer may be present in an amount of from
95% to 60% by weight in the starting material.
[0020] According to one embodiment, the extruable polymer is
polypropylene, the particulate filler is wood sawdust having a
particle size of about 60 mesh, the wood sawdust being present in
an amount from about 20% to 30% by weight in the starting
material.
[0021] The rate of drawing through the drawing die may be
sufficient to cause the composite material to have a density of
from 0.5 to 0.9 of the density of the starting material.
[0022] A composite material is provided which includes a filler for
enhancing the physical properties of the composite material and a
binding agent mixed with the filler for permitting extrusion of the
composite material in a plastic extrusion process to provide a
predetermined dispersion pattern of the filler in the composite
material.
[0023] The filler may be natural or synthetic fiber and the binding
agent may be a polymer.
[0024] A composite material is provided which comprises a
particulate material dispersed in an oriented polymer.
[0025] The particulate material may be wood sawdust having a
particle size of about 60 mesh. The oriented polymer may be
polyethylene with the oriented polymer forming from 60% to 95% by
weight of the composite material.
[0026] A strip of composite material is provided, suitable for
strip flooring and having parallel upper and lower faces with first
and second parallel edges extending between the upper and lower
faces. The first edge has a tongue extending therefrom with
parallel upper and lower curved surfaces. The second edge has a
groove extending thereinto with curved parallel opposite sides. The
tongue and the groove are of complimentary curvature for the tongue
of a first strip to be rotatable into registration with the groove
of an adjacent strip to resist lateral separation between the first
strip, and the adjacent strips by interference between the upper
and lower curved surfaces and the curved parallel opposite
sides.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Preferred embodiments of the present invention will now be
described, by way of example only, with reference to the attached
Figures, wherein:
[0028] FIG. 1 illustrates a method of extruding a composite
material according to the present invention;
[0029] FIG. 2 illustrates an extruder for extruding same;
[0030] FIG. 3 illustrates an extruded billet of the composite
material;
[0031] FIG. 4 is an end elevation of a tongue and groove joint
which may be formed in the extrusion method of the present
invention;
[0032] FIG. 5 is a cross-sectional illustration of an alternate
forming method according to the present invention; and
[0033] FIG. 6 is a schematic illustration of an automated process
of the method of FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Referring now to FIG. 1 a method of extruding a composite
material is shown generally at 10. A filler 12 and a binding agent
14 are placed in a feeder 16. Feeder 16 feeds a predetermined
volume of filler 12 and binding agent 14 into melt extruder 18. In
an embodiment, feeder 16 is a gravimetric feeder controlled by an
external CPU 17. Melt extruder 18 mixes filler 12 and binding agent
14 to form feedstock 20, as is well known to those of skill in the
art. Feedstock 20 then passes to an extruder 22, and is extruded to
produce a composite material 24.
[0035] Filler 12 can be a natural fibre, such as wood and
agricultural fibres such as hemp, flax, straw or wheat; a synthetic
fibre such as nylon, polyethylene terephthalate, glass or
polypropylene fibre with a polyethylene matrix. Filler 12 can also
be a mineral based filler such as slate, talc, vermiculite or mica.
In a presently preferred embodiment, filler 12 is a wood fibre
concentrate. Filler 12 has a mesh in the range of 10-300, more
preferably in the range 10-150. In the presently preferred
embodiment filler 12 has a 60 mesh.
[0036] Binding agent 14 is a polymer or other suitable extrudable
plastic, such as polypropylene (PP), polyethylene (PE) or polyvinyl
chloride (PVC). Binding agent 14 forms approximately 55-95% by
weight of feedstock 20. Other ranges for the % weight of binding
agent 14 in feedstock 20 may be appropriate depending on the filler
chosen. More limited ranges of 60-95% or 70-90% may be required
depending on the chosen filler 12.
[0037] Once filler 12 and binding agent 14 have been fed to feeder
16, they pass to melt extruder 18. A predetermined volume of filler
12, in accordance with the % weight of binding agent 14 that is
used, and binding agent 14 are mixed in melt extruder 18 and
extruded in a conventional manner to produce feedstock 20. The
resultant feedstock 20 is fed by melt extruder 18 to extruder
22.
[0038] FIG. 2 illustrates a preferred embodiment of extruder 22.
Extruder 22 has a ram 34, a pressure chamber 30 and a die 38. The
method and apparatus of the extrusion process are detailed in U.S.
Pat. No. 5,169,589 to Francoeur et al., U.S. Pat. No. 5,204,045 to
Courval et al. and U.S. Pat. No. 5,169,587 to Courval, the contents
of which are incorporated herein by reference. The method of the
extrusion process produces a highly oriented polymer profile. The
resultant composite material 24, produced by this process,
generally has a higher tensile strength and modulus than feedstock
20. In the presently preferred embodiment an oriented product 48 of
composite material 24, formed with a wood-fibre concentrate filler
is produced in standard widths of 2 inches, 3 inches or 6 inches
(5.08 cm, 7.62 cm or 15.24 cm).
[0039] FIG. 3 illustrates an oriented product 48 of composite
material 24. Produced in the manner outlined above, composite
material 24 has striations 50 of filler 12, formed in a dispersion
pattern with a wood-grain appearance. The resultant oriented
product 48 resembles hard wood flooring and can be adapted to be
used in commercial applications as such. Appropriate attaching
means, such as a tongue and groove, or snap lock, can be
subsequently tooled in to the oriented material to create a product
that can be attached in series in a commercial application, such as
flooring or furniture manufacturing. Surface treatment can also be
applied to the billet for increasing the surface properties of the
billet, such as adding a protective coating, such as polyurethane,
to protect the surface layer from scratching.
[0040] By varying parameters of the ram extrusion process, such as
temperature, pressure and die contours, properties of composite
material 24 can be changed. The properties of composite material 24
can also be changed by varying amounts of filler 12, and by
changing the composition of filler 12. This will affect the
physical properties of composite material 24, such as colour,
texture, electrical conductivity, glow in the dark and fire
retardancy.
[0041] The oriented product 48 of composite material 24 can be
manipulated in order to meet a manufacturer's specifications with
regards to the final commercial application. Oriented product 48
can be cut and shaped during the ram extruding process. In the
presently preferred embodiment, composite material 24 is extruded
as oriented product 48 of varying specifications, however it can
also be extruded as a sheet for use in commercial applications such
as indoor and outdoor furniture manufacturing.
[0042] The present invention provides a new composite material, and
a method and apparatus for extruding the composite material. The
invention includes the initial mixing of a binding agent and a
filler to produce a feedstock which is subsequently extruded as a
billet of a composite material. The composite material is stronger
and more durable then the starting materials. The composite
material also contains striations of the filler which allows the
manufacturer to produce a composite material that can reflect the
image of a natural product and can be used in commercial
applications such as floor coverings. The properties of the
composite material can also be changed, in order to met the
requirements for the commercial application of the product, by the
incorporation of different types of filler and by varying the
amount of filler used.
[0043] FIG. 4 is an end elevation showing a particularly
advantageous tongue and groove configuration which can be formed
along opposite edges of the oriented product 48 of the composite
material 24. A first edge 50 has a tongue 52 formed thereon having
an upper concave face 54 and a lower convex face 56. The opposite
edge 60 has a groove 62 with an upper convex edge 64 and a lower
concave edge 66. The tongue 52 and the groove 62 register to allow
the tongue to be initially inserted into the groove 62 of an
adjacent strip of oriented product 48 at a relative angle on the
order of 45.degree. between the adjacent strips of oriented product
48 and then rotated into place in the direction of arrow 70 so that
the tongue 52 nests in the groove 62 with the adjacent strips of
oriented product in a parallel side by side configuration.
[0044] Once the tongue 52 and the groove 62 are nested, removal in
a lateral direction indicated by arrows 80 is prevented first by
interference between an upper edge 58 of the tongue and a depending
edge 68 of the groove. Lateral separation is further inhibited by
an upwardly extending edge 69 of the groove 62 interfering with a
lowermost portion 59 of the tongue 52.
[0045] Extrusion rates for the composite material 24 will vary
depending on various factors such as the particular composite
material 24 selected, the degree of reduction, and the
cross-sectional area of the extruded strip or column. Extrusion
rates are however rather slow and rates on the order of six inches
per minute (6 in./min.) are not atypical.
[0046] It has been found that rather than extruding the composite
material 24, by pressing it through the die 38, the composite
material may be drawn through the die 38. FIG. 5 illustrates such a
drawing process.
[0047] One manner of drawing the composite material through the die
38 is to initially commence by extrusion, as discussed above. Once
an end 100 of the oriented product 48 begins to emerge from the die
38, the end may be grasped, such as by a clamp 102 and pulled. The
pulling would typically be done with no further pressing force
being applied and yields an oriented end product 104.
[0048] In tests, pulling rates of up to 14 ft./min. (fourteen feet
per minute) have been achieved which was limited by machine
capacity. It is expected that pulling rates of 20 ft./min. (twenty
feet per minute) are entirely feasible.
[0049] The properties of the oriented end product 104 produced by
drawing are significantly different than those produced by
extrusion. By way of example, a starting billet 110 was first
formed by combining a wood fiber plastic concentrate containing 60%
wood particles of about 60 mesh size and 50% polypropylene with
virgin polypropylene in a 1:1 ratio. This yielded a composition
having about 30% wood fiber and 70% polypropylene. The resulting
combination was heated and extruded to form the billet 110.
[0050] The billet 110 was of rectangular cross-section measuring
about two inches by two inches (2".times.2"). The billet 110 was
heated in an oven to about 150.degree. C. (ie. close to but below
the melting point of polypropylene which is about 160.degree. C.)
and transferred to the pressure chamber 30 and initially forced
through the die 38. The extruded material was then grasped using
the clamp 102 and drawn at a rate of about 4 ft./min. (Four feet
per minute) and once it had been entirely drawn through the die 38,
allowed to cool into the oriented end product 104. The draw ratio
(i.e. the initial cross-sectional area divided by the final
cross-sectional area) was 10:4.
[0051] The oriented end product 104 bore a remarkable similarity
both in look and in feel to wood. The oriented end product 104
diminished in density by about half compared to the starting billet
110. The density of the oriented end product 104 was about 0.59
g/cc (grams per cubic centimeter) compared to a density of about 1
g/cc for the starting billet 110.
[0052] The oriented end product 104 could be shaped as if it were
wood and in planing and sawing behaved very much like wood
producing shavings remarkably like wood shavings and sawdust
remarkably like wood sawdust. The oriented end product 104 received
both nails and screws without splitting much like wood.
[0053] In testing, the oriented end product was found to have a
density and flexural strength not unlike wood and a modulus of
elasticity of about half that of wood. Typical properties were a
density of 0.059 g/cc, flexural strength of 6,353 lb/in.sup.2 and a
modulus of elasticity of 799,298 lb/in.sup.2. Unlike wood however
the oriented product 104 was virtually non adsorptive to water.
[0054] Although testing was carried out using a starting billet
110, the process can no doubt be automated as schematically
illustrated in FIG. 6. FIG. 6 shows an extruder 120 in which feed
materials 121 may be blended and extruded through a die 122 into a
first column 124. The first column 124 is fed through a first haul
off 125 into a continuous furnace 126 where its temperature is
adjusted to a drawing temperature. The first haul off 125 acts
against the extrusion direction to maintain extrusion pressure and
to support the column 124. The temperature adjusted first column
124 is fed into a drawing die 128 at the exit of which it is
reduced in size to a second column 130. The second column 130 is
grasped by a suitable haul off 132 such as sold under the trademark
CATERPILLAR as it exits the drawing die 128. The haul off 132 then
pulls the second column 130 at a desired rate to form an oriented
product 138.
[0055] The above-described embodiments of the invention are
intended to be examples of the present invention and alterations
and modifications may be effected thereto, by those of skill in the
art, without departing from the scope of the invention which is
defined solely by the claims appended hereto.
* * * * *