U.S. patent application number 11/544566 was filed with the patent office on 2007-04-19 for variegated composites and related methods of manufacture.
This patent application is currently assigned to Trex Company, Inc.. Invention is credited to Blair Dolinar.
Application Number | 20070087180 11/544566 |
Document ID | / |
Family ID | 35449313 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070087180 |
Kind Code |
A1 |
Dolinar; Blair |
April 19, 2007 |
Variegated composites and related methods of manufacture
Abstract
Embodiments of the invention include a composite. The composite
includes a crystalline polymer, a plurality of wood fibers blended
with the crystalline polymer, an outer surface, and an amorphous
polymer visible on the outer surface. The amorphous polymer has a
first color and the blend of the crystalline polymer and the
plurality of wood fibers has a second color different from the
first color. The invention also includes a method of manufacturing
the wood-plastic composites such that one polymer is shifted in the
composite relative to the other polymer.
Inventors: |
Dolinar; Blair; (Winchester,
VA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Trex Company, Inc.
|
Family ID: |
35449313 |
Appl. No.: |
11/544566 |
Filed: |
October 10, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10862448 |
Jun 8, 2004 |
|
|
|
11544566 |
Oct 10, 2006 |
|
|
|
Current U.S.
Class: |
428/292.1 |
Current CPC
Class: |
Y10T 428/25 20150115;
C08L 97/02 20130101; Y10T 428/249925 20150401; Y10T 428/31989
20150401; Y10T 428/249924 20150401; Y10T 428/254 20150115; C08L
97/02 20130101; C08L 2666/02 20130101 |
Class at
Publication: |
428/292.1 |
International
Class: |
D04H 3/00 20060101
D04H003/00 |
Claims
1-20. (canceled)
21. A method of manufacturing a wood-plastic composite including a
profile body, comprising: providing a crystalline polymer;
providing a plurality of wood fibers; providing an amorphous
polymer; melting the crystalline polymer; melting the amorphous
polymer; first mixing the crystalline polymer and the plurality of
wood fibers to form a substantially homogenous feed; second mixing
the amorphous polymer with the substantially homogenous feed of the
crystalline polymer and the plurality of wood fibers to form a
heterogeneous feed; and forming the profile body from the
heterogeneous feed, the profile body including an outer surface
evincing a first color associated with the amorphous polymer and a
second color associated with the substantially homogenous feed, the
second color being different from the first color.
22. The method of claim 21, further comprising forming streaks of
the first color on the outer surface.
23. The method of claim 21, further comprising forming streaks of
the amorphous polymer on the outer surface.
24. The method of claim 21, further comprising shifting the
amorphous polymer towards the outer surface.
25. The method of claim 21, further comprising variegating the
outer surface.
26. The method of claim 21, further comprising providing at least
one of a single screw extruder and a double screw extruder, wherein
the step of forming includes extruding the heterogeneous feed via
the at least one of the single-screw extruder and the double screw
extruder.
27. The method of claim 21, wherein the step of second mixing
includes forming the first color from the amorphous polymer and
forming the second color from the substantially homogenous feed
including the crystalline polymer and the plurality of wood
fibers.
28. The method of claim 21, further comprising providing another
amorphous polymer; melting the another amorphous polymer; and
mixing the another amorphous polymer with the amorphous polymer and
the substantially homogenous feed including the crystalline polymer
and the plurality of wood fibers, wherein the step of forming
includes forming the profile body such that the outer surface
evinces a third color associated with the another amorphous polymer
different from the first color and the second color.
29. The method of claim 21, further comprising providing a core,
wherein the step of forming the profile body includes forming the
profile body around at least a portion of the core.
30. The method of claim 21, further comprising providing a colorant
having a third color different from the first color and the second
color; and blending the colorant with one of the crystalline
polymer and the amorphous polymer so as to turn the one of the
crystalline polymer and the amorphous polymer the third color.
31. A method of manufacturing a wood-plastic composite including a
profile body, comprising: providing a first polymer; providing a
plurality of wood fibers; providing a second polymer not
substantially soluble in the first polymer; melting the first
polymer; melting the second polymer; first mixing the second
polymer and the plurality of wood fibers to form a substantially
homogenous feed; second mixing the first polymer with the
substantially homogenous feed to form a heterogeneous feed; and
forming the profile body from the heterogeneous feed, the profile
body including an outer surface evincing a first color associated
with the first polymer and a second color associated with the
substantially homogenous feed, the second color being different
from the first color.
32. The method of claim 31, further comprising forming streaks of
the first color on the outer surface.
33. The method of claim 31, further comprising forming streaks of
the first polymer on the outer surface.
34. The method of claim 31, further comprising shifting the first
polymer towards the outer surface.
35. The method of claim 31, further comprising variegating the
outer surface.
36. The method of claim 31, further comprising providing at least
one of a single screw extruder and a double screw extruder, wherein
the step of forming includes extruding the heterogeneous feed via
the at least one of the single-screw extruder and the double screw
extruder.
37. The method of claim 31, wherein the step of second mixing
includes forming the first color from the first polymer and forming
the second color from the substantially homogenous feed including
the second polymer and the plurality of wood fibers.
38. The method of claim 31, further comprising providing a third
polymer not substantially soluble in the second polymer; melting
the third polymer; and mixing the third polymer with the first
polymer and the substantially homogenous feed including the second
polymer and the plurality of wood fibers, wherein the step of
forming includes forming the profile body such that the outer
surface deliberately evinces a third color associated with the
third polymer different from the first color and the second
color.
39. The method of claim 31, further comprising providing a core,
wherein the step of forming the profile body includes forming the
profile body around at least a portion of the core.
40. The method of claim 31, further comprising providing a colorant
having a third color different from the first color and the second
color; and blending the colorant with one of the first polymer and
the second polymer so as to turn the one of the first polymer and
the second polymer the third color.
41. A method of manufacturing a wood-plastic composite including a
profile body, comprising: providing a first polymer, a plurality of
wood fibers, a second polymer not substantially soluble in the
first polymer, and an additive; melting the first polymer and the
second polymer; first blending the additive with the second polymer
to form a substantially homogenous blend; second blending the first
polymer and the plurality of wood fibers to form a substantially
homogenous feed; mixing the substantially homogenous blend with the
substantially homogenous feed of the first polymer and the
plurality of wood fibers to form a heterogeneous feed; forming the
profile body with an outer surface from the heterogeneous feed; and
shifting the substantially homogenous blend towards the outer
surface such that at least a portion of the substantially
homogenous blend is visible on the outer surface.
42. The method of claim 41, wherein the additive is one or more of
a pigment, a mold inhibitor, a microorganism growth inhibitor, and
a mildew inhibitor.
43. The method of claim 41, wherein the substantially homogeneous
blend substantially covers an entire side of the profile body.
44. The method of claim 41, wherein the additive is not blended
with either of the first polymer or the wood fibers.
45. The method of claim 41, wherein the additive is soluble in the
second polymer and not soluble in the first polymer.
46. The method of claim 21, further comprising preventing the
plurality of wood fibers from being dispersed throughout the
amorphous polymer during the step of second mixing.
47. The method of claim 31, further comprising preventing the
plurality of wood fibers from being dispersed throughout the first
polymer during the step of second mixing.
48. The method of claim 41, further comprising preventing the
plurality of wood fibers from being dispersed throughout the first
polymer during the step of mixing.
49. The method of claim 21, wherein providing the amorphous polymer
includes providing enough of the amorphous polymer so as to result
in the profile body including between about 0% and about 5% of the
amorphous polymer by weight.
50. The method of claim 31, wherein providing the first polymer
includes providing enough of the first polymer so as to result in
the profile body including between about 0% and about 5% of the
first polymer by weight.
51. The method of claim 41, wherein providing the first polymer
includes providing enough of the first polymer so as to result in
the profile body including between about 0% and about 5% of the
first polymer by weight.
52. The method of claim 21, wherein providing the amorphous polymer
includes providing enough of the amorphous polymer so as to result
in the profile body including about 2% of the amorphous polymer by
weight.
53. The method of claim 31, wherein providing the first polymer
includes providing enough of the first polymer so as to result in
the profile body including about 2% of the first polymer by
weight.
54. The method of claim 41, wherein providing the first polymer
includes providing enough of the first polymer so as to result in
the profile body including about 2% of the first polymer by
weight.
55. The method of claim 21, wherein the amorphous polymer is one of
a polystyrene and polycarbonate.
56. The method of claim 31, wherein the amorphous polymer is one of
a polystyrene and polycarbonate.
57. The method of claim 41, wherein the amorphous polymer is one of
a polystyrene and polycarbonate.
Description
DESCRIPTION OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention is directed to variegated wood-plastic
composites and methods of manufacturing the same. For example, the
surfaces of the wood-plastic composites may be variegated by
varying the polymer composition of the wood-plastic composite. The
invention also includes a method of manufacturing the wood-plastic
composites such that one polymer is shifted in the composite
relative to the other polymer.
[0003] 2. Background of the Invention
[0004] Wooden components are commonly used in manufacturing decks
and related assemblies. Wooden components includes strings of wood
fibers having various colors (e.g., rings on trees) that give the
surface of the wooden component a streaked appearance. The streaked
appearance imparts an aesthetically pleasing look and feel to the
deck component. One disadvantage of using wooden components,
however, is that the wood may be susceptible to rotting, weather,
insects, and/or wear and tear, and may require the acquisition and
processing of wood which may involve environmentally unfriendly
processing techniques, such as the clear cutting of forests and the
use of hazardous chemicals.
[0005] A more environmentally friendly alternative to using wooden
components in manufacturing decks and related assemblies is to use
a wood-plastic composite made of crystalline polymers. Examples of
suitable wood-plastic composites made of crystalline polymers and
related methods of manufacture are disclosed in co-owned U.S. Pat.
Nos. 5,851,469 and 6,527,532, co-pending and co-owned U.S. patent
application Ser. No. 10/292,672 filed Nov. 12, 2002, and co-pending
and co-owned U.S. patent application Ser. No. 10/668,368 filed Sep.
24, 2003, the entirety of all of which are incorporated herein by
reference.
[0006] Wood-plastic composites made of crystalline polymers,
however, tend to have solid one color surfaces. This is at least
partially due to the sharp melting point temperatures of
crystalline polymers and the tendency of crystalline polymers to
easily blend together. Thus, even if a plurality of crystalline
polymers having a plurality of different colors are used to
manufacture a wood-plastic composites, the plurality of different
colors will blend together in the manufacturing process and the
composite will emerge having a surface with one solid color. In any
case, the resultant composite does not have a streaked
appearance.
SUMMARY OF THE INVENTION
[0007] An exemplary embodiment of the invention includes a
composite. The composite comprises a crystalline polymer, a
plurality of wood fibers blended with the crystalline polymer, an
outer surface, and an amorphous polymer visible on the outer
surface. The amorphous polymer has a first color and the blend of
the crystalline polymer and the plurality of wood fibers has a
second color different from the first color.
[0008] In various embodiments, the invention may include one or
more of the following aspects: the crystalline polymer may be at
least one of polypropylene and polyethylene; the amorphous polymer
may be a styrenic polymer; the outer surface may include streaks of
the first color; the amorphous polymer may have a melting
temperature that is substantially the same as a melting temperature
of the crystalline polymer; the outer surface may be variegated; a
first portion of the outer surface may have the first color and a
second portion of the outer surface may have the second color;
another amorphous polymer visible on the outer surface; the another
amorphous polymer may have a third color different from the first
color and the second color; the composite may be at least one of a
building material, a decking material, and a decking board; a
colorant may be blended with one of the crystalline polymer and the
amorphous polymer.
[0009] Another embodiment of the invention includes a composite.
The composite may include a first polymer, a plurality of wood
fibers blended with the first polymer, an outer surface, and a
second polymer configured to resist blending with the first
polymer. The composite may be manufactured such that the second
polymer is deliberately visible on the outer surface. The blend of
the first polymer and the plurality of wood fibers may have a first
color and the second polymer may have a second color different from
the first color. The second polymer may not be substantially
soluble in the first polymer.
[0010] In various embodiments, the invention may include one or
more of the following aspects: the first polymer may be at least
one of polypropylene and polyethylene; the second polymer may be a
styrenic polymer; the outer surface may include streaks of the
second color; the first polymer may have a melting temperature that
is substantially the same as a melting temperature of the second
polymer; the outer surface may be variegated; a first portion of
the outer surface may have the first color and a second portion of
the outer surface has the second color; a third polymer may be
configured to resist blending with the first polymer; the composite
may be manufactured such that the third polymer is deliberately
visible on the outer surface; the third polymer may have a third
color different from the first color and the second color; the
composite may be at least one of a building material, a decking
material, and a decking board; a colorant blended with one of the
first polymer and the second polymer.
[0011] A further embodiment of the invention may include a method
of manufacturing a wood-plastic composite. The method may include
providing a crystalline polymer, providing a plurality of wood
fibers, providing an amorphous polymer, melting the crystalline
polymer, melting the amorphous polymer, mixing the amorphous
polymer with the crystalline polymer and the plurality of wood
fibers to form a feed, and forming a profile body from the feed,
the profile body including an outer surface evincing a first color
and a second color different from the first color.
[0012] In various embodiments, the invention may include one or
more of the following aspects: forming streaks of the first color
on the outer surface; forming streaks of the amorphous polymer on
the outer surface; shifting the amorphous polymer towards the outer
surface; variegating the outer surface; providing at least one of a
single screw extruder and a double screw extruder; the step of
extruding may include extruding the feed via the at least one of
the single-screw extruder and the double screw extruder; the step
of mixing may include forming the first color from the amorphous
polymer and forming the second color from a blend of the
crystalline polymer and the plurality of wood fibers; providing
another amorphous polymer; melting the another amorphous polymer;
mixing the another amorphous polymer with the amorphous polymer,
the crystalline polymer, and the plurality of wood fibers; the step
of extruding may include forming the profile body such that the
outer surface evinces a third color different from the first color
and the second color; providing a core; the step of forming the
profile body may include forming the profile body around at least a
portion of the core; providing a colorant; blending the colorant
with one of the crystalline polymer and the amorphous polymer.
[0013] Yet another embodiment of the invention may include a method
of manufacturing a wood-plastic composite. The method may include
providing a first polymer, providing a plurality of wood fibers,
providing a second polymer not substantially soluble in the first
polymer, melting the first polymer, melting the second polymer,
mixing the second polymer with the first polymer and the plurality
of wood fibers to form a feed, and forming a profile body from the
feed, the profile body including an outer surface deliberately
evincing a first color and a second color different from the first
color.
[0014] In various embodiments, the invention may include one or
more of the following aspects: forming streaks of the first color
on the outer surface; forming streaks of the first polymer on the
outer surface; shifting the first polymer towards the outer
surface; variegating the outer surface; providing at least one of a
single screw extruder and a double screw extruder; the step of
extruding may include extruding the feed via the at least one of
the single-screw extruder and the double screw extruder; the step
of mixing may include forming the first color from the first
polymer and forming the second color from a blend of the second
polymer and the plurality of wood fibers; providing a third polymer
not substantially soluble in the first polymer; melting the third
polymer; mixing the third polymer with the first polymer, the
second polymer, and the plurality of wood fibers; the step of
extruding may include forming the profile body such that the outer
surface deliberately evinces a third color different from the first
color and the second color; providing a core; the step of forming
the profile body may include forming the profile body around at
least a portion of the core; providing a colorant; blending the
colorant with one of the first polymer and the second polymer.
[0015] A yet further embodiment of the invention may include a
method of manufacturing a wood-plastic composite. The method may
include providing a first polymer, a plurality of wood fibers, a
second polymer not substantially soluble in the first polymer, and
an additive, melting the first polymer and the second polymer,
blending the additive with the second polymer to form a blend,
mixing the blend with the first polymer and the plurality of wood
fibers to form a feed, forming a profile body with an outer surface
from the feed, and shifting the blend towards the outer surface
such that at least a portion of the blend is visible on the outer
surface.
[0016] In various embodiments, the invention may include one or
more of the following aspects: the additive may be one or more of a
pigment, a mold inhibitor, and a mildew inhibitor; the blend may
substantially cover an entire side of the profile body; the
additive may not be blended with either of the first polymer or the
wood fibers; the additive may be soluble in the second polymer and
not be soluble in the first polymer.
[0017] Additional objects and advantages of the invention will be
set forth in part in the description which follows, and in part
will be obvious from the description, or may be learned by practice
of the invention. The objects and advantages of the invention will
be realized and attained by means of the elements and combinations
particularly pointed out in the appended claims.
[0018] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate several
embodiments of the invention and together with the description,
serve to explain the principles of the invention.
[0020] FIG. 1 is a perspective view of a composite according to an
embodiment of the invention.
[0021] FIG. 2A is a schematic view of the composite of FIG. 1.
[0022] FIG. 2B is a top schematic view of a composite according to
another embodiment of the invention.
[0023] FIG. 2C is a top schematic view of a composite according to
a further embodiment of the invention.
[0024] FIG. 3A is a side schematic view of the composite of FIG.
1.
[0025] FIG. 3B is a side schematic view of a composite according to
yet another embodiment of the invention.
[0026] FIG. 3C is a side schematic view of a composite according to
still another embodiment of the invention.
[0027] FIG. 4A is a schematic view of a process of manufacturing
the composite of FIG. 1.
[0028] FIG. 4B is a schematic view of a process of manufacturing a
composite according to a yet further embodiment of the
invention.
[0029] FIG. 4C is a schematic view of a process of manufacturing a
composite according to still another embodiment of the
invention.
DESCRIPTION OF THE EMBODIMENTS
[0030] Reference will now be made in detail to the exemplary
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0031] An exemplary embodiment of the invention includes a
composite. As shown in FIGS. 1, 2A-2C, and 3A-3C, composite 1 may
include a first polymer 2, a plurality of wood fibers 3 blended
with first polymer 2 to form a blend 4, an outer surface 5, and a
second polymer 6 configured to resist blending with first polymer 2
(e.g., second polymer 6 is not substantially soluble in first
polymer 2). Second polymer 6 may be visible on outer surface 5.
Blend 4 of first polymer 2 and wood fibers 3 may have a first color
and second polymer 6 may have a second color different from the
first color.
[0032] Composite 1 may be used as a decking component or any other
suitable building material. For example, as shown in FIG. 1,
composite 1 may be used as a decking board, railing, railing post,
and/or decking beam. In another example, composite 1 may be used to
construct any portions of homes, walkways, shelters, and/or any
other desirable structure.
[0033] Composite 1 may include a first polymer 2 which may be a
crystalline polymer 2. Crystalline polymer 2 is preferably at least
one of high density polyethylene (HDPE), low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), and polypropylene
(PP). The polypropylene may be a homo- and/or a co-polymer
polypropylene. However, any crystalline polymer may be used, such
as one or more polyamides (PA), nylons, polyoxymethylenes,
polybutylene terephthalates (PBT), polyethylene terephthalates
(PET), and/or acetals. Crystalline polymer 2 may have any suitable
size, shape, and/or configuration to be melted, mixed with wood
fibers 3, and/or extruded into a dimensionally stable profile.
Crystalline polymer 2 may have any suitable size, shape, and/or
configuration to be used in any of the apparatuses or methods
disclosed in co-owned U.S. Pat. Nos. 5,851,469 and 6,527,532,
co-pending and co-owned U.S. patent application Ser. No. 10/292,672
filed Nov. 12, 2002, and co-pending and co-owned U.S. patent
application Ser. No. 10/668,368 filed Sep. 24, 2003, the entirety
of all of which are incorporated herein by reference. For example,
crystalline polymer 2 may be in the form of a pellet, a flake, a
film, and/or a scrap form. In another example, crystalline polymer
2 may range in size from reactor powder having a diameter of about
0.01650 inches to pieces of plastic having dimensions (e.g.,
length, width, height, depth, and/or diameter) between about 1 inch
and about 100 feet. More typically, however, crystalline polymer 2
is film scrap having dimensions (e.g., length, width, height,
depth, and/or diameter) between about 0.0787 inches and 0.25
inches.
[0034] Composite 1 may include a second polymer 6 which may be an
amorphous polymer 6. Amorphous polymer 6 is preferably a styrenic
polymer such as polystrene (PS). However, any amorphous polymer may
be used in composite 1, such as one or more of Impact PS,
polymethylmethacrylates (PMMA), polyvinyl chlorides (PVC),
acrylonitrile-butadine-styrene copolymers (ABS), thermoplastic
polyurethanes (TPU), styrene acrylonitrile copolymers (SAN),
polyphenyl oxide (PPO), acryla-styrene butyl-acrylate or acrylate
styrene acrylonitrile (either of which may be abbreviated as ASA),
and/or polycarbonates (PC). In a preferred embodiment, ABS is used.
Amorphous polymer 6 may have any suitable size, shape, and/or
configuration. For example, amorphous polymer 6 may be in the form
of pellets and/or flakes. In a preferred embodiment, amorphous
polymer 6 has a high polarity and/or decreased melt flow relative
to crystalline polymer 2. The size of the amorphous polymer 6 used
may be dependent on these and other properties of amorphous polymer
6. For example, amorphous polymer 6 may be a substantially solid
chunk having dimensions (e.g., length, width, diameter, depth,
and/or height) between about 0.25 inches and 0.0165 inches or may
have a substantially spherical shape having an average diameter of
about 0.0165 inches.
[0035] In its Solid form, polymers generally are capable of forming
different structures depending on the structure of the polymer
chain as well as the processing conditions. In amorphous polymers
6, the polymer chain is substantially random and unordered in
structure, while in crystalline polymers 2, the structure of the
polymer backbone is a substantially regular, ordered structure such
that the polymer can be tightly packed, although in general most
crystalline polymer 2 are only semicrystalline. This is because the
exact make up and details of the polymer backbone will determine
whether the polymer is capable of crystallizing. For example, PVC,
depending on the characteristics of its backbone, may be either
crystalline (isotactic or syndiotactic structures) or amorphous
(atactic structure). Accordingly, due to these differences in
polymer structures, amorphous polymers 6 generally cannot fit into
the semicrystalline structures of crystalline polymers 2 (e.g.,
like incompatible puzzle pieces), and amorphous polymers 6 may also
exhibit polarities that prevent it from being integrated into the
semicrystalline structures of crystalline polymers 2 (e.g., like
oil and water). Thus, amorphous polymer 6 has a different
solubility parameter then crystalline polymer 2. The polarities of
amorphous polymer 6 may also allow it to retain polar pigments
(e.g., which may be background color 9) that may not bind as well
to crystalline polymer 2 which is either devoid and/or has a lower
polarity than amorphous polymer 6.
[0036] Composite 1 may include a plurality of wood fibers 3. Wood
fibers 3 may be from any type of suitable wood, for example, one or
more hardwoods and/or softwoods. Wood fibers 3 may be of any
suitable shape and/or size, and may be configured to be suitably
blended with crystalline polymer 2 such that a mixture or blend 4
of wood fibers 3 and crystalline polymer 2 appears substantially
homogenous in color and/or consistency. For example, wood fibers 3
may have dimensions (e.g., length, width, depth, diameter, and/or
height) ranging from about 6 inches to about 0.25 inches, all the
way down to substantially spherical shapes having an average
diameter of about 0.00079 inches. More typically, however, wood
fibers 3 may range in size from substantially spherical shapes
having an average diameter of about 0.07870 inches to substantially
spherical shapes having an average diameter of about 0.007 inches.
In various embodiments, the wood fibers 3 may be mixed with and/or
be replaced with any suitable organic or inorganic filler material,
including one or more of grass, wheat hulls, corn stocks, corn
ears, nuts, nut shells, peanuts, peanut shells, walnut, walnut
shells, sand, clay, dirt, and concrete.
[0037] Second polymer 6 may resist blending with first polymer 2
(e.g., second polymer 6 may not be soluble in first polymer 2 and
vice versa). For example, if second polymer 6 is an amorphous
polymer and first polymer 2 is a crystalline polymer, even when
both polymers are in a melted state, the two polymers may resist
blending with each other. Thus, while amorphous polymer 6 may be
somewhat dispersed throughout crystalline polymer 2, amorphous
polymer 6 may not be evenly distributed or blended throughout
crystalline polymer 2 (e.g., amorphous polymer 6 may migrate to the
outer surface 5). Accordingly, amorphous polymer 6 may form
"clumps" and/or "pockets" in crystalline polymer 2, and thus
regions of amorphous polymer 6 may be clearly discernible in the
otherwise substantially homogenous blend of crystalline polymer 2
and wood fibers 3. For example, amorphous polymer 6 may have a
different color and/or consistency than any combination of
crystalline polymer 2 and wood fibers 3.
[0038] Composite 1 may have a variegated outer surface 5 (i.e., a
first portion of outer surface 5 may have a first color and a
second portion of outer surface 5 may have a second color different
from the first color). For example, outer surface 5 may include
streaks 16. Streaks 16 may run in any direction, may have any size
and/or shape, may be disposed in and/or on any portion of composite
1, may have any configuration, and/or may have a color different
from the rest of composite 1. For example, streaks 16 may assist
composite 1 in obtaining a more aesthetically pleasing wood-like
appearance. Streaks 16 are preferably present toward outer surface
5. Any surface of composite 1, for example inner surfaces of
composite 1, may have streaks 16.
[0039] Due to the properties of the amorphous polymer 6 set forth
above, and especially with regard to its possible tendency to
resist blending with crystalline polymers, amorphous polymer 6 may
be responsible for streaks 16 on outer surface 5 of composite 1.
For example, when melted and mixed with crystalline polymer 2 and
wood fiber blend, amorphous polymer 6 may be dispersed in the blend
(e.g., mixed but not blended with the blend) such that streaks 16
correspond to the location of amorphous polymer 6. As shown in FIG.
3A, amorphous polymer 6 is preferably disposed toward outer surface
5 of composite 1.
[0040] Composite 1 may have an outer surface 5 that includes 50% or
more of second polymer 6 (e.g., more than 50% of the surface area
of outer surface 5 of composite 1 may be second polymer 6). For
example, as shown in FIG. 3C substantially entire portions of outer
surface 5 (e.g., one or more of the top, bottom, sides, and/or ends
of composite 1) may be composed of second polymer 6. Thus, in some
configurations, composite 1 may appear as is if it was coextruded
such that second polymer 6 substantially surrounds first polymer 2.
In such a configuration, entire portions of outer surface 5 may
appear to have substantially one color (e.g., the color of second
polymer 6 after it has been extruded using any of the exemplary
methods set forth herein), even though composite 1 may include one
or more components (e.g., first polymer 2, wood fibers 3, blend 4,
second polymer 6, background color 9, and/or blend 18) having
different colors either prior to, during, or following
processing.
[0041] Amorphous polymer 6 may have a melting temperature that is
substantially the same as a melting temperature of crystalline
polymer 2, as shown in the following table: TABLE-US-00001 Polymer
Melting Temperature Range (.degree. C.) HDPE
125.degree.-132.degree. LLDPE 110.degree.-125.degree. LDPE
103.degree.-110.degree. PP-Homo 160.degree.-175.degree.
PP-Copolymer 150.degree.-175.degree. PS 74.degree.-105.degree. ABS
88.degree.-125.degree. SAN 100.degree.-200.degree. PS-Rubber Mod.
93.degree.-105.degree.
Thus, for polymers listed above, non-melting mixing (e.g., mixing
without blending) of amorphous polymer 6 and crystalline polymer 2
may occur between about 140.degree. C. and about 180.degree. C.,
depending on the exact polymers used. Thus, the present invention
has the advantage that even though the polymers used (e.g.,
crystalline polymer 2 and amorphous polymer 6) may have
substantially the same melting temperature, the two polymers will
still resist blending.
[0042] Composite i may include a third polymer 7. For example,
third polymer 7 may be an amorphous polymer. Third polymer 7 may be
the same amorphous polymer as second polymer 6, or may be a
different amorphous polymer. Third polymer 7 may have the same
color as second polymer 6, or may have a different color. Third
polymer 7 may behave similarly to second polymer 6. For example,
third polymer 7 may form streaks 16 on outer surface 5 of composite
1 that have a color different from the rest of outer surface 5.
Thus, composite 1 may have a plurality of streaks against a base
background color of composite 1, with a first set 16A of streaks 16
having a first color and second set 16B of streaks 16 having a
second color different from the first color. One of ordinary skill
in the art would realize that composite 1 may include any suitable
number of crystalline polymers, wood fiber types, and/or amorphous
polymers. In the example where amorphous polymers cover
substantially entire portions of composite 1 (e.g., as set forth in
FIG. 3C), composite 1 may still evince more than color, for
example, one color may correspond to the presence of amorphous
polymer 6 on some portions of outer surface 5 while another color
may correspond to the presence of amorphous polymer 7 on other
portions of outer surface 5.
[0043] As shown in FIG. 3B, composite 1 may include a core 8. Core
8 may have any suitable size, shape, configuration, and/or
composition. Core 8 may be configured to impart strength or any
other suitable property to composite 1. Core 8 may itself be a
wood-plastic composite. The mixture of crystalline polymer 2,
amorphous polymer 6, and/or wood fibers 3 may be disposed around
core 8 and/or integrated (e.g., fused) with core 8.
[0044] Composite 1 may include a background color 9 and/or pigment.
Background color 9 may be configured to color one or more of
crystalline polymer 2, amorphous polymer 6, amorphous polymer 7,
and/or wood fibers 3. For example, background color 9 may be
processed with crystalline polymer 2 and/or wood fiber 3 such that
background color 9 permeates crystalline polymer 2 and/or wood
fiber 3 and forms blend 4 (e.g., background color 9 may permeate
associate/engage with portions of the polymer chain of crystalline
polymer 2). However, blend 4 may then be processed with amorphous
polymer 6 in a suitable manner such that background color 9 does
not substantially permeate amorphous polymer 6. For example, the
processing of blend 4 and amorphous polymer 6 may occur at a lower
temperature than the processing of background color 9, crystalline
polymer 2, and/or wood fiber 3. In another example, the
aforementioned structures of the respective polymer chains of
crystalline polymer 2 and amorphous polymer 6 may be substantially
incompatible and/or resistant to blending (e.g., at any
temperature). Accordingly, background color 9 may substantially
remain attached to/within crystalline polymer 2 and/or blend 4 and
not appreciably permeate amorphous polymer 6.
[0045] In various embodiments, background color 9 may be added to
amorphous polymer 6 in addition to and/or instead of crystalline
polymer 2, and any of the aforementioned characteristics may be
applicable to amorphous polymer 6 (e.g., because amorphous polymer
6 and crystalline polymer 2 are configured to resist blending,
background color 9 will substantially remain associated with
amorphous polymer 6 and not crystalline polymer 2). Indeed, adding
background color 9 to amorphous polymer 6 and then mixing amorphous
polymer 6 (which already has been mixed with background color 9)
with either a colored or uncolored blend 4 is the preferred
embodiment. Background color 9 may have a polarity that increases
the likelihood that background color 9 will remain associated with
amorphous polymer 6. (e.g., background color 9 and amorphous
polymer 6 may have polarities that may cause them to be attracted
to each other like magnets with opposing polarities) and not become
associated with crystalline polymer 2 (e.g., background color 9 and
crystalline polymer 2 may have polarities that may cause them to
repel each other like magnets with substantially the same
polarities).
[0046] In another embodiment, composite 1 may include another
material, compound, and/or additive intermixed with at least one of
crystalline polymer 2 and amorphous polymer 6, for example, in
substantially the same way as background color 9 is intermixed with
at least one of crystalline polymer 2 and amorphous polymer 6 as
set forth herein, and especially in the previous paragraph. For
example, the another material may include a compound that, either
on its own or when mixed with at least one of crystalline polymer 2
and amorphous polymer 6, causes at least portions of composite 1
(and preferably outer surface 5 of composite 1) to be resistant to
molding and/or mildewing (e.g., keeps the level of microorganisms,
mildew, and/or mold in and/or on a composite 1 lower than about 0.1
parts per million). An example of such a material may include a
dichloro-octyl-isothiazolone (DCOIT) biostabilizer (e.g., biocide),
such as certain grades of VINYZENE.TM. manufactured by ROHM AND
HAAS.TM. (or other isothiazolones), however, any other suitable
material (e.g., biostabiliter or biocide) that prevents and/or
reduces molding and/or mildewing either alone or when mixed with at
least one of crystalline polymer 2 and amorphous polymer 6 is also
acceptable. Examples of acceptable methods for determining whether
a particular material (e.g., biostabilizer, biocide) suitably
prevents and/or reduces mold and/or mildew on composite 1 may
include American Association for Testing Materials (ASTM.TM.)
standards ASTM.TM. D-1413-99 SOIL-BLACK, ASTM.TM. D-4445-91 SAP
STAIN, ASTM.TM. E-1428-99 PINK STAIN, ASTM.TM. G-21-96 MIXED FUNGI,
ASTM.TM. D-5583-00 SINGLE CULTURE, and/or MILITARY STANDARD 810-E
HUMIDITY CHAMBER, and/or their equivalents. Indeed, in any of the
embodiments set forth herein, the another material, such as the
DCOIT biostabilizer, may be substituted for background color 9 and
may exhibit any of the properties of background color 9 relative to
the crystalline polymer 2, amorphous polymer 6, and/or blend 4 in
any portion of the process.
[0047] The DCOIT biostabilizer (examples of which may include
VINYZENE.TM. IT 4000 Series, VINYZENE.TM. IT 4010 Series, and
VINYZENE.TM. SB 27, all of which are manufactured by ROHM AND
HAAS.TM.) may be dispersed throughout the crystalline polymer 2,
but preferably the amorphous polymer 6, in any concentration
suitable to prevent or reduce mold or mildew growth on the
composite 1, for example, between about 800 parts per million and
about 2000 parts per million and/or between about 1000 parts per
million and 1200 parts per million. The DCOIT biostabilizer may
have a thermal stability of about 220.degree. C. and/or a
solubility in water of about 6 parts per million.
[0048] Another example of a suitable biostabilizer may be
10.10'-oxybisphenoxarsine (OBPA), examples of which may include
VINYZENE.TM. BP 5-2 Series, VINYZENE.TM. BP 5-5 Series,
VINYZENE.TM. SB 1, and VINYZENE.TM. SB 1 Series. The OBPA
biostabilizer may be dispersed throughout the crystalline polymer
2, but preferably the amorphous polymer 6, in any concentration
suitable to prevent or reduce mold or mildew growth on the
composite 1, for example, between about 200 parts per million and
about 500 parts per million. The OBPA biostabilizer may have a
thermal stability of about 300.degree. C. and/or a solubility in
water of about 6 parts per million.
[0049] A further example of a suitable biostabilizer may be
octyl-isothiazoline (OIT), examples of which may include
VINYZENE.TM. IT 3000 Series, VINYZENE.TM. IT 3010 Series,
VINYZENE.TM. IT 3025 DIDP, and VINYZENE.TM. SB 8. The OIT
biostabilizer may be dispersed throughout the crystalline polymer
2, but preferably the amorphous polymer 6, in any concentration
suitable to prevent or reduce mold or mildew growth on the
composite 1, for example, between about 800 parts per million and
about 1200 parts per million. The OIT biostabilizer may have a
thermal stability of about 220.degree. C. and/or a solubility in
water of about 500 parts per million.
[0050] Yet another example of a suitable biostabilizer may be
trichlorophenoxyphenol (TCPP), examples of which may include
VINYZENE.TM. SB 30. The TCPP biostabilizer may be dispersed
throughout the crystalline polymer 2, but preferably the amorphous
polymer 6, in any concentration suitable to prevent or reduce mold
or mildew growth on the composite 1, for example, between about 800
parts per million and about 1200 parts per million. The TCPP
biostabilizer may have a thermal stability of about 230.degree. C.
and/or a solubility in water of about 10 parts per million.
[0051] A yet further example of a suitable biostabilizer includes
biostabilizers that prevent and/or reduce the growth of any of the
following exemplary fungi, bacteria, and/or actinomycetes on
composite 1: Altemaria, Aureobasidium, Curvularia, Aspergillus,
Penicillium, Fusarium, Bigrospora, Chaetomium, Gliocladium,
Helminthsporium, and/or all of the subspecies of the aforementioned
fungi, bacteria, and/or actinomycetes.
[0052] Still another example of a suitable biostabilizer (e.g.,
biocide) includes biostabilizers having one or more of the
following features: substantially non-toxic; safe and
environmentally friendly; broad spectrum; compatibility with
formulation; leach and ultraviolet resistant; has sufficient
thermal stability; and ease of use and handling.
[0053] A still further example of a suitable biostabilizer may
include zinc borate, which may be in the form of a crystalline
powder having a solubility in water of about 2800 parts per million
and a particle sizes between about 1-2 microns.
[0054] Other examples of suitable biostabilizers (e.g., biocides)
and methods for determining suitable. biostabilizers for
wood-plastic and other composites were disclosed in a presentation
entitled Maintaining the Aesthetic Quality of WPC Decking with
Isothiazolone Biocide by Peter Dylingowski, which was presented on
May 20, 2003 at the 7.sup.th International Conference on Wood-Fiber
Plastic Composites, the entirety of which is incorporated herein by
reference.
[0055] An exemplary embodiment of the invention includes a method
of manufacturing a wood-plastic composite. As shown in FIGS. 4A-4C,
the method may include providing a first polymer 2, providing a
plurality of wood fibers 3, providing a second polymer 6 configured
to resist blending with first polymer 2, melting first polymer 2,
melting second polymer 6, mixing second polymer 6 with first
polymer 2 and wood fibers 3 to form a feed 10, and forming a
profile body 1. Profile body 1 may include an outer surface 5
deliberately evincing a first color and a second color different
from the first color. Profile body 1 may also include an outer
surface 5 being substantially composed of second polymer 6, with a
cross-sectional profile of profile body 1 showing that a layer of
second polymer 6 may be substantially disposed around blend 4 of
first polymer 2 and wood fibers 3.
[0056] First polymer 2 may include a crystalline polymer 2.
Crystalline polymer 2 is preferably at least one of high density
polyethylene (HDPE), low density polyethylene (LDPE), linear low
density polyethylene (LLDPE), and polypropylene (PP), however, any
crystalline polymer may be used in composite 1, such as one or more
polyamides (PA), nylons, polyoxymethylenes, polybutylene
terephthalates (PBT), polyethylene terephthalates (PET), and/or
acetals. First polymer 2 may be provided in any suitable form
(e.g., pellets, flakes, sheets, etc.) to be melted, mixed with wood
fibers 3, and/or extruded into a dimensionally stable profile.
First polymer 2 may have any suitable size, shape, and/or
configuration to be used in any of the apparatuses or methods
disclosed in co-owned U.S. Pat. Nos. 5,851,469 and 6,527,532,
co-pending and co-owned U.S. patent application Ser. No. 10/292,672
filed Nov. 12, 2002, and co-pending and co-owned U.S. patent
application Ser. No. 10/668,368 filed Sep. 24, 2003, the entirety
of all of which are incorporated herein by reference. First polymer
2 may be processed prior to extruding the feed 10 using any
suitable method. For example, first polymer 2 may be chopped,
purified, shredded, heated, and/or demoistured. In various
embodiments, first polymer 2 may be heated (e.g., by shear friction
with the apparatus or by the application of external thermal
energy) to completely melt, partially melt, and/or improve
processability.
[0057] Crystalline polymers 2 may be selected because they have a
specific color (e.g., be mixed with a certain color dye) and/or
composition (e.g., allows background color 9 to suitable permeate
its structure). However, because crystalline polymers 2 (and/or its
additives such as background color 9) tend to blend and form a
substantially homogenous color, the specific colors and/or
compositions of crystalline polymers 2 used in the process need not
be tightly controlled. Some specific dyes may affect the resulting
color of profile body 1 more than other dyes. One of ordinary skill
in the art may control crystalline polymers 2 input into the
process in order to achieve the desired resultant color for outer
surface 5. Moreover, the resultant color of crystalline polymers 2
after processing (e.g., heating and/or extrusion) may be different
from the initial colors of crystalline polymers 2. Crystalline
polymer 2 may have any suitable size, shape, and/or configuration,
exemplary parameters for which have already been set forth
herein.
[0058] Second polymer 6 may include an amorphous polymer. Amorphous
polymer 6 is preferably a styrenic polymer such as polystrene (PS),
however, any amorphous polymer may be used in composite 1, such as
one or more of Impact PS, polymethylmethacrylates (PMMA), polyvinyl
chlorides (PVC), acrylonitrile-butadine-styrene copolymers (ABS),
thermoplastic polyurethanes (TPU), styrene acrylonitrile copolymers
(SAN), polyphenyl oxide (PPO), acryla-styrene butyl-acrylate or
acrylate styrene acrylonitrile (either of which may be abbreviated
as ASA), and/or polycarbonates (PC). Second polymer 6 may be
provided in any suitable form (e.g., pellets, flakes, sheets,
films, etc.) Second polymer 6 may be processed prior to extruding
the feed 10 using any suitable method. For example, second polymer
6 may be chopped, shredded, heated, purified, and/or demoistured.
In another example, background color may be added to second polymer
6, and then second polymer 6 may introduced into a processing
apparatus, such as extruder 15, substantially cold (e.g., without
processing) to be mixed with blend 4 and/or into the processing
apparatus as close to the extruder die 19 of the processing
apparatus as possible to be extruded with blend 4.
[0059] Amorphous polymer 6 used may be selected based on its color
and/or composition. Amorphous polymer 6 may have an initial color
and/or resultant color that is different from the initial color
and/or resultant color of the one or more crystalline polymers
(with or without wood fibers 3) that amorphous polymer 6 is being
mixed with. For example, crystalline polymers 2, after processing
(with or without wood fibers 3 and/or background color 9), may
result in a substantially gray color, while amorphous polymer 6,
after processing, may result in a substantially black color.
Amorphous polymer 6 may have any suitable size, shape, and/or
configuration. For example, amorphous polymer 6 may be provided in
flake or pellet form.
[0060] Crystalline polymer 2 and/or amorphous polymer 6 may be
melted using any suitable method. For example, crystalline polymer
2 and/or amorphous polymer 6 may be heated using in an external
heat source (e.g., a flame in a heater 13) or may be heated through
kinetic energy (e.g., by passing through a barrel 12 with a
rotating screw 11, or passing through extruder die 19). Crystalline
polymer 2 and/or amorphous polymer 6 may be melted at any point in
the composite manufacturing process prior to forming profile body
1. Crystalline polymer 2 and/or amorphous polymer 6 may be heated
separately and/or together. In a preferred embodiment, crystalline
polymer 2 and/or wood-fibers 3 may be heated and blended to form
blend 4. Crystalline polymer 2 may be heated substantially
throughout crystalline polymer 2 and/or enough to improve
processability (e.g., mixing and/or blending).
[0061] Wood fibers 3 may be from any type of suitable wood, for
example, one or more hardwoods and/or softwoods. Wood fibers 3 may
also be mixed with and/or replaced by any organic or inorganic
filler such as those set forth herein. Wood fibers 3 may be of any
suitable shape and/or size, and may be configured to be suitably
blended with crystalline polymer 2 such that a mixture of wood
fibers 3 and crystalline polymer 2 appears substantially homogenous
in color. Wood fibers 3 may be processed prior to forming profile
body 1 using any suitable method. For example, wood fibers 3 may be
chopped, shredded, heated, purified, and/or demoisturized. Wood
fibers 3 may be dried prior to being blended with crystalline
polymer 2 to form blend 4. In some cases, pieces of wood fiber 3
may be discernible in blend 4, however, wood fiber 3 will still
typically have the same homogenous color as the rest of blend
4.
[0062] Crystalline polymer 2 may be blended in a processor 13 with
wood fibers 3 such that blend 4 is substantially homogenous. For
example, blend 4 may have one substantially solid color and/or have
a substantially uniform consistency. Blend 4 may be formed using
any suitable method. Crystalline polymer 2 and wood fibers 3 may be
blended by placing them together either before, during, or after
crystalline polymer 2 and/or wood fibers 3 are dried. Crystalline
polymer 2 and wood fibers 3 may be blended using applied heat
and/or mechanical agitation. Such blending may be accomplished by
an extruder, high shear device, and/or a low shear mixer with or
without the application of heat.
[0063] Second polymer 6 may be mixed with first polymer 2 and wood
fibers 3 to form a feed 10 in any suitable order, any suitable
ratio, and using any suitable method. For example, first polymer 2,
second polymer 6, and plurality of wood fibers 3 may be mixed as
they are advanced by one or more screws 11 in a barrel 12 and/or
extruded through die 19. Second polymer 6 may be mixed with first
polymer 2 and wood fibers 3 at any time prior to extruding the feed
and in any relative order. For example, first polymer 2 may be
blended with wood fibers 3, the blend may be heated, and then
second polymer 6 may be added to the blend. In another example,
first polymer 2, second polymer 6, and wood fibers 3 may be
combined at substantially the same time and mixed simultaneously.
Second polymer 6 may be mixed with first polymer 2 and wood fibers
3 such that the mixture does not blend. For example, the mixture
may be heated to a temperature that allows mixing but not
blending.
[0064] In another example, second polymer 6 may be added to blend 4
to form feed 10 just prior to extruding feed 10 through extruder
die 19. Thus, heating of second polymer 6 may only occur just after
introducing second polymer 6 into blend 4 and/or during extrusion
of feed 10 through extruder die 19. Accordingly, second polymer 6
may experience less of a heat history than any of first polymer 2,
wood fibers 3, and/or blend 4, which may assist in preventing
blending.
[0065] In a further example, the structures (e.g., crystalline
structures, lack of crystalline structures, polymer backbones,
polarity, compositions, etc.) of first polymer 2 and second polymer
6 may assist in preventing the polymers 2, 6, from substantially
blending. Exemplary percentages of first polymer 2, second polymer
6, and wood fibers 3 are listed herein, however, generally, the
percentage of first polymer 2 will exceed the percentage of second
polymer 6.
[0066] In various embodiments, composite 1 may include between
about 100% and about 20% of crystalline polymer 2, between about 5%
and about 0% of amorphous polymer 6, and between about 0% and about
80% wood fiber or other filler. In a preferred embodiment,
composite 1 may include between about 60% and about 53% of
crystalline polymer 2, about 2% of amorphous polymer 6, and between
about 45% and about 38% wood fiber or other filler
[0067] Besides having a more natural, smooth, non-monolithic,
and/or three-dimensional looking surface, composites 1 discussed
herein may have other advantages. For example, composite 1 may be
less susceptible to mold and mildew and/or may be more durable.
Crystalline polymer 2 and amorphous polymer 6 do not blend in
composites 1. Accordingly, the minor component (in this case,
amorphous polymer 6) may migrate to the outer surface 5 of
composite 1. When the minor component migrates to outer surface 5
of composite 1, the minor component may tend to coat at least
portions of outer surface 5 (e.g., top, bottom, and/or side
surfaces) with a polymer rich coating that does not absorb
moisture, and thus allows outer surface 5 to resist molding and/or
mildewing. Moreover, additional additives, such as mold and mildew
resistant compounds (e.g., DCOIT biostabilizers or other suitable
anti-fungi.bacteria materials/compounds, examples of which are set
forth herein, or other materials having other desirable properties
for composite 1), may be added to amorphous polymer 6 at any point
before or during the manufacturing process of composite 1. During
the addition of the additive to amorphous polymer 6, the additive
and amorphous polymer 6 may be processed so as to substantially
disperse the additive through the matrix of amorphous polymer 6.
Once again, because amorphous polymer 6 may migrate to outer
surface 5 of composite 1, amorphous polymer 6 with mildew resistant
additives (or other materials) may coat at least portions of outer
surface 5. Some exemplary reasons why amorphous polymer 6 may
migrate toward outer surface 5 of composite 1 are set forth herein,
and especially below.
[0068] This type of delivery of the mold and mildew resistant
materials and/or compounds, examples of which are set forth herein,
(or other compounds with other desirable properties) to specific
portions of composite 1 may have many advantages. For example, the
compounds themselves may be relatively expensive and/or including
too much of the compound in composite 1 may compromise some
structural and/or aesthetic properties of composite 1. Thus, there
may be a need to minimize the amount of the compound in composite 1
by delivering the compound to portions of the composite 1 where the
compound may be most effective. In the case of mildew and/or mold
resistant compounds (examples of which are set forth herein), such
compounds may be most effective on at least portions of outer
surface 5 of composite 1. Accordingly, because the properties
(e.g., crystalline structure, solubility, or other properties like
or similar to those set forth herein) of first polymer 2 (e.g.,
crystalline polymer) and second polymer 6 (e.g., amorphous polymer)
causes second polymer 6, when extruded, to migrate away from first
polymer 2 (e.g., with or without wood fibers 3) and/or toward outer
surface 5 of composite 1, second polymer 6 may be used as a vehicle
to deliver desirable compounds on and/or toward outer surface 5. In
some cases, if the property of the compound is desirable along
large portions of outer surface 5, then second polymer 6 with the
desirable compound may be disposed along entire portions of outer
surface 5, for example, as set forth in FIG. 3C.
[0069] Profile body 1 with an outer surface 5 may be formed using
any suitable method. For example, the mixture including first
polymer 2 (e.g., crystalline polymer), second polymer 6 (e.g.,
amorphous polymer), and wood fibers 3 may be extruded through a die
19 to form profile body 1. Feed 10 may be extruded using either a
single screw extruder or a double screw extruder to form profile
body 1. Feed 10 may also be formed into profile body 1 using any
suitable method.
[0070] Outer surface 5 of profile body 1 may be variegated. Streaks
16 may be formed on outer surface 5 of profile body 1. For example,
if crystalline polymer 2 and amorphous polymer 6 are mixed, the
chemical properties of the two polymers and/or the processing
conditions (e.g., temperature, extrusion rate, mixing rate that the
two polymers are subjected to) may prevent them from blending with
each other and forming a homogenous color. Accordingly, "clumps" or
"pockets" of amorphous polymer 6 may be dispersed through
crystalline polymer 2 and vice versa. As the mixture of amorphous
polymer 6 and crystalline polymer 2 (with or without wood fibers 3)
is extruded through the die 19, amorphous polymer 6 may tend to go
towards outer surface 5 of profile body 1, for example, due the
pressures exerted on feed 10 during extrusion. In another example,
due to the molecular structure of both crystalline polymer 2 and
amorphous polymer 6, the polymer chain of amorphous polymer 6
cannot interlock easily with the polymer chain and/or matrix of
crystalline polymer 2. Accordingly, amorphous polymer 6 may tend to
separate from the polymer matrix of crystalline polymer 2 and go to
outer surface 5 so as to form its own solid polymer matrix of
amorphous polymer 6. As amorphous polymer 6 reaches surface 5,
because amorphous polymer 6 may have a different initial color
and/or different resultant color as the rest of profile body 1
(i.e., blend 4 of crystalline polymer 2 and wood fibers 3), streaks
16 of amorphous polymer 6 may be readily discernible on outer
surface 5. Streaks 16 may be generally perpendicular to a
cross-section of die 19 through which profile body 1 is extruded.
However, streaks 16 may be in any direction, and have any other
shape and/or configuration, for example, similar to those set forth
in FIGS. 2A-2C.
[0071] In another example, entire portions of outer surface 5 may
be composed of amorphous polymer 6, for example, as shown in FIG.
3C. In such an example, the processing may have been such that
amorphous polymer 6 forms "clumps" or "pockets" (e.g., as set forth
in the previous paragraph) around substantially all of blend 4 so
as to form a substantially solid matrix around blend 4 (e.g., with
or without wood fibers 3). Any suitable proportions of amorphous
polymer 6, crystalline polymer 2, wood-fibers 3, blend 4, blend 18,
background color 9, and another other material or compound set
forth herein are contemplated as being discernible on outer surface
5.
[0072] The method may also include providing another amorphous
polymer 7, melting another amorphous polymer 7, and mixing another
amorphous polymer 7 with amorphous polymer 6, crystalline polymer
2, and/or wood fibers 3. With the addition of additional amorphous
polymer 7, the step of extruding may include forming profile body 1
such that outer surface 5 deliberately evinces a third color
different from the first color and the second color due to
additional amorphous polymer 7.
[0073] Another amorphous polymer 7 may be selected because its
initial color and/or resultant color may be different from an
initial color and/or resultant color of one or more of crystalline
polymer 2 and/or wood fibers 3. Another amorphous polymer 7 may
processed and/or behave similarly to other amorphous polymers 6,
thus, streaks 16B of another amorphous polymer 7 may be formed on
outer surface 5 of profile body 1. Streaks 16B from another
amorphous polymer 7 may be of a color different from either the
base color of profile body 1 and/or the color of streaks 16A from
amorphous polymer 6.
[0074] As shown in FIG. 4B, the method may also include providing a
core 8 and forming profile body 1 around at least a portion of core
8. Core 8 may be a wood-plastic composite or any other suitable
composite. Core 8 may have a cross-sectional area smaller than a
cross-sectional area of die 19. Core 8 may be fed by extruder 15
through die 19 such that core 8 advances through substantially the
center of die 19 without contacting any portion of die 19 itself.
Extruder 15 and/or die 19 may then deposit an outer surface 5 on
core 8 that has more than one color (e.g., variegated and/or
streaked) using one or more of the methods set forth herein. The
variegated surface 5 may be bonded to core 8 using any suitable
method, for example, when variegated surface 5 is co-extruded onto
core 8, a portion of core 8 may melt and intermix with variegated
surface 5 such that core 8 and the variegated surface 5 are
substantially fused. Accordingly, the resultant product may be a
building material with a core 8 having a wood-plastic composite
having a deliberately variegated outer surface 5 formed around it.
Such a resultant product may be desirable, for example, to impart
strength to the component (e.g., by providing a core component
having a high strength such as aluminum or steel).
[0075] The method also may include the use of a background color 9.
As shown in FIG. 4B, background color 9 may be added to crystalline
polymer 2 and/or wood fiber 3 (e.g., blend 4) to impart a color to
blend 4 different from an initial color of blend 4, crystalline
polymer 2, and/or wood fiber 3. Background color 9, crystalline
polymer 2, wood fibers 3, and/or blend 4 may be processed by
processor 13 using any suitable apparatus and/or method to form
resultant blend 4. Resultant blend 4 may then be transferred to
extruder 15 and processed with amorphous polymer 6 to form profile
body 1 with streaks 16 or other variations of outer surface 5 as
set forth herein. Background color 9 may be added to any step of
the process and/or any component or subcomponent of the process at
any time prior to extrusion through die 19.
[0076] In a preferred embodiment, as shown in FIG. 4C, background
color 9 may be added to amorphous polymer 6 to impart a color to
amorphous polymer 6 different from an initial color of amorphous
polymer 6. Background color 9 and/or amorphous polymer 6 may be
processed by processor 17 using any suitable apparatus and/or
method to form resultant blend 18 of amorphous polymer 6 and
background color 9. Resultant blend 18 may then be transferred to
extruder 15 and processed with crystalline polymer 2, wood fibers
3, and/or blend 4 to form profile body 1 with streaks 16 or other
variations of outer surface 5 as set forth herein. Once again,
background color 9 may be added to any step of the process and/or
any component or subcomponent of the process at any time prior to
extrusion through die 19.
[0077] One of ordinary skill in the art will recognize that some
aspects of the invention may be multiplied so as to form different
embodiments of the invention. For example, there may be a plurality
of crystalline polymers, a plurality of types of wood fibers,
and/or a plurality of amorphous polymers used.
[0078] One of ordinary skill of art will further recognize that
some of the aspects of set forth herein may be combined with other
aspects set forth herein to form different embodiments of the
invention. For example, composite 1 with streaks having multiple
colors may also include a core.
[0079] One of ordinary skill in the art will also recognize that
some of the aspects set forth herein may be removed to form
different embodiments of the invention. For example, crystalline
polymer 2 and wood fibers need not be blended prior to mixing them
with amorphous polymer 6.
[0080] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with a
true scope and spirit of the invention being indicated by the
following claims.
* * * * *