U.S. patent application number 12/578654 was filed with the patent office on 2010-02-11 for exterior building material having a hollow thin wall profile and an embossed low gloss surface.
Invention is credited to KENNETH D. BOSLER, MARK DUNMIRE, THOMAS GILBERT, CHRISTOPHER B. PIETRUCZYNIK, MARK SUCHYNA.
Application Number | 20100032861 12/578654 |
Document ID | / |
Family ID | 38920846 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100032861 |
Kind Code |
A1 |
PIETRUCZYNIK; CHRISTOPHER B. ;
et al. |
February 11, 2010 |
Exterior Building Material Having a Hollow Thin Wall Profile and an
Embossed Low Gloss Surface
Abstract
A building product which includes a hollow extrudate, unitary
reinforcing ribs resisting collapse of the hollow extrudate and, in
an embodiment, an exterior surface comprises a low gloss, textured
pattern having a gloss level of less than about 50 on a 60.degree.
glossmeter, in which the textured pattern extends for about 2-20
feet. Methods and an apparatus for manufacturing such products are
also provided by this invention.
Inventors: |
PIETRUCZYNIK; CHRISTOPHER B.;
(NORRISTOWN, PA) ; BOSLER; KENNETH D.;
(WARMINSTER, PA) ; GILBERT; THOMAS; (CLARKLAKE,
MI) ; SUCHYNA; MARK; (LANCASTER, NY) ;
DUNMIRE; MARK; (TONAWANDA, NY) |
Correspondence
Address: |
DUANE MORRIS LLP - Philadelphia;IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103-4196
US
|
Family ID: |
38920846 |
Appl. No.: |
12/578654 |
Filed: |
October 14, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11773108 |
Jul 3, 2007 |
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12578654 |
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Current U.S.
Class: |
264/177.17 ;
425/113 |
Current CPC
Class: |
B29C 48/12 20190201;
B29C 48/07 20190201; B29C 48/0017 20190201; B29C 48/175 20190201;
B29C 48/11 20190201; B29L 2031/60 20130101; B29C 48/304 20190201;
B29K 2995/0072 20130101; E04C 2/20 20130101; B29C 59/06 20130101;
B29C 59/04 20130101; E04C 2/36 20130101; B29C 48/15 20190201; B29C
48/001 20190201; B29L 2024/006 20130101 |
Class at
Publication: |
264/177.17 ;
425/113 |
International
Class: |
B29C 47/04 20060101
B29C047/04; B29C 47/08 20060101 B29C047/08 |
Claims
1. A method of making a building product, comprising: extruding a
unitary extrudate; forming unitary reinforcing ribs on the unitary
extrudate; embossing a continuous length pattern of surface
topography features in exterior sides of the unitary extrudate; and
supporting the sides to resist collapse thereof while heat and
forces are applied during embossing.
2. The method of claim 1 further comprising: supporting the
interior of the extrudate by mandrels during embossing to resist
collapse thereof.
3. The method of claim 1, comprising: extruding the unitary
extrudate as a polymeric thin wall member with a unitary capstock
layer and with streaker material in the unitary extrudate.
4. The method of claim 3, comprising: vacuum embossing an exterior
of the thin wall member to form a low gloss textured pattern having
a gloss level of less than about 50 on a 60.degree. glossmeter;
calibrating a profile of the thin wall member; cooling said profile
after calibrating the profile; and cutting said thin wall member to
a length of about 2 feet to about 20 feet.
5. The method of claim 1, comprising: extruding the unitary
extrudate as a substrate and a weather resistant capstock layer
coextruded with the substrate, wherein the capstock layer retains
its thickness beneath the low gloss textured pattern to maximize a
weather resistant thickness of the capstock layer.
6. Apparatus for making a hollow polymeric building product,
comprising: an extruder for extruding a unitary polymeric extrudate
with or without a capstock layer; a vacuum embosser for embossing
surface texture in exterior surfaces of the extrudate while
supporting interior surfaces of the extrudate; and a forming die
for forming the extrudate into the polymeric building product.
7. The apparatus of claim 6, comprising: mandrels supporting the
interior surfaces of the extrudate while embossing the surface
texture, or a mold belt supporting the interior surfaces of the
extrudate while embossing the surface texture, or a mold chamber
supporting the interior surfaces of the extrudate while embossing
the surface texture.
8. The method of claim 1, comprising: shaping the extrudate by
calibrating thereof after embossing.
9. The method of claim 1 further comprising: supporting the
extrudate with mandrels in spaces between the ribs during embossing
to resist collapse of the exterior sides.
10. The method of claim 1 further comprising: embossing the
exterior sides with the surface topography features duplicating
surface topography features of a material occurring in nature.
11. The method of claim 1 further comprising: embossing the
exterior sides by vacuum embossing the exterior sides with a mold
belt, the mold belt providing a continuous pattern of the surface
topography features, wherein the continuous pattern of surface
topography features duplicate surface topography features of a
material occurring in nature.
12. The method of claim 1, comprising: extruding the exterior sides
with a substrate layer and a unitary capstock layer on the
substrate layer; and embossing the exterior sides with the surface
topography features duplicating surface topography features of a
material occurring in nature.
13. The method of claim 1, comprising: extruding the exterior sides
with a substrate layer and a unitary capstock layer on the
substrate layer; and embossing the exterior sides by vacuum
embossing the exterior sides with a mold belt, the mold belt
providing a continuous pattern of the surface topography features,
wherein the continuous pattern of surface topography features
duplicate surface topography features of a material occurring in
nature.
14. The method of claim 1, comprising: extruding the exterior sides
with color streaker material forming color streaks in the exterior
sides.
15. The method of claim 1, comprising: extruding the exterior sides
with color streaker material forming color streaks in the exterior
sides; and embossing the exterior sides by vacuum embossing the
exterior sides with a mold belt, the mold belt providing a
continuous pattern of the surface topography features, wherein the
continuous pattern of surface topography features duplicate surface
topography features of a material occurring in nature.
16. The method of claim 1, comprising: extruding the exterior sides
with a substrate layer, a unitary capstock layer on the substrate
layer and color streaker material forming color streaks in the
exterior sides; and embossing the exterior sides by vacuum
embossing the exterior sides with a mold belt, the mold belt
providing a continuous pattern of the surface topography features,
wherein the continuous pattern of surface topography features
duplicate surface topography features of a material occurring in
nature.
17. The method of claim 1, comprising: extruding the extrudate with
the continuous exterior sides joining a unitary hinge about which
the continuous unitary sides are pivoted by folding the continuous
unitary sides; and folding the continuous unitary sides to provide
a hollow extrudate before calibrating the extrudate by sizing or
shaping thereof.
18. The method of claim 1, comprising: embossing the exterior sides
by vacuum embossing the exterior sides with a mold belt, the mold
belt providing a continuous low gloss pattern of the surface
topography features having a gloss level of less than about 50 on a
60.degree. glossmeter.
20. Apparatus for making a hollow polymeric building product,
comprising: an extruder for extruding an extrudate having
continuous exterior sides and unitary reinforcing ribs; an embosser
for embossing the exterior sides to form surface topography
features on the exterior sides; a support for supporting the
extrudate during embossing to resist collapse of the exterior
sides; and a calibrator calibrating the extrudate by sizing or
shaping thereof.
21. The apparatus of claim 20 wherein the support comprises
mandrels in spaces between the ribs during embossing to resist
collapse of the exterior sides.
22. The apparatus of claim 20 further comprising: the embosser
having a continuous pattern of the surface topography features
duplicating surface topography features of a material occurring in
nature.
23. The apparatus of claim 20 wherein the embosser comprises a mold
belt for vacuum embossing the exterior sides with the mold belt,
the mold belt providing a continuous pattern of the surface
topography features, wherein the continuous pattern of surface
topography features duplicate surface topography features of a
material occurring in nature.
24. The apparatus of claim 20 wherein the extruder extrudes the
exterior sides with a substrate layer and a unitary capstock layer
on the substrate layer, and the embosser embosses the exterior
sides with the surface topography features duplicating surface
topography features of a material occurring in nature.
25. The apparatus of claim 20 wherein the extruder extrudes the
exterior sides with a substrate layer and a unitary capstock layer
on the substrate layer, and the embosser embosses the exterior
sides by vacuum embossing the exterior sides with a mold belt, the
mold belt providing a continuous pattern of the surface topography
features, wherein the continuous pattern of surface topography
features duplicate surface topography features of a material
occurring in nature.
26. The apparatus of claim 20 wherein the extruder extrudes the
exterior sides with color streaker material forming color streaks
in the exterior sides.
27. The apparatus of claim 20 wherein the extruder extrudes the
exterior sides with color streaker material forming color streaks
in the exterior sides, and the embosser embosses the exterior sides
by vacuum embossing the exterior sides with a mold belt, the mold
belt providing a continuous pattern of the surface topography
features, wherein the continuous pattern of surface topography
features duplicate surface topography features of a material
occurring in nature.
28. The apparatus of claim 20 wherein the extruder extrudes the
exterior sides with a substrate layer, a unitary capstock layer on
the substrate layer and color streaker material forming color
streaks in the exterior sides, and the embosser embosses the
exterior sides by vacuum embossing the exterior sides with a mold
belt, the mold belt providing a continuous pattern of the surface
topography features, wherein the continuous pattern of surface
topography features duplicate surface topography features of a
material occurring in nature.
29. The apparatus of claim 20 wherein the extruder extrudes the
extrudate with the continuous exterior sides joining a unitary
hinge about which the continuous unitary sides are pivoted by
folding the continuous unitary sides to provide a hollow
extrudate.
30. The apparatus of claim 20 wherein the embosser embosses the
exterior sides by vacuum embossing the exterior sides with a mold
belt, the mold belt providing a continuous low gloss pattern of the
surface topography features having a gloss level of less than about
50 on a 60.degree. glossmeter.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. application
Ser. No. 11/773,108, filed Jul. 3, 2007 (D0932-00774). This
application claims the benefit of both U.S. Provisional Application
No. 60/807,081, filed Jul. 12, 2006 and U.S. Provisional
Application No. 60/807,082, filed Jul. 12, 2006.
[0002] This application is related to U.S. application Ser. No.
10/281,795, filed Oct. 28, 2002, of Bycong Jo and John Peavey,
entitled "Plastic Decking System Reinforced with Fiberglass
Reinforced Thermoplastic Composites" (D0932-00200); U.S.
application Ser. No. 09/190,038, filed Nov. 12, 1998, of Thomas
Gilbert, David Jacobson, and Rick Lappin, entitled "Shaped
Polymeric Articles" (D0932-00088); U.S. application Ser. No.
09/735,681, filed Dec. 13, 2000, of Thomas Gilbert, Kenneth Bosler
and Steven Booz, entitled "Staggered Look Shake Siding", now U.S.
Pat. No. 6,737,008, issued May 18, 2004 (D0932-00230); and U.S.
application Ser. No. 11/247,620, filed Oct. 11, 2005, of Jong P.
Jeng, entitled "Building Material Having a Fluorocarbon Based
Capstock layer and Process of Manufacturing Same with Less
Dimensional Distortion" (D0932-00593); the entirety of which are
incorporated herein by reference. The Examiner's attention is drawn
to the prior art cited, or otherwise of record, in these related
applications.
FIELD OF THE INVENTION
[0003] This invention relates to substantially hollow, closed, thin
wall profile building materials having a low gloss textured pattern
disposed continuously along one or more surfaces thereof.
BACKGROUND OF THE INVENTION
[0004] There have been a number of polymeric products made to look
like natural wood for decking and siding applications. Such
products are formed by extrusion and embossing processes, or by
injection molding in a pattern mold to simulate a wood grain or
pattern. Such products comprise a painted or otherwise "decorated"
or printed pattern to simulate wood or other materials, such as
marble or natural stone, for example. Such teachings are provided
in Franco et al., US2005/0053767; Giacchino, US 2005/0127345; Barre
et al., U.S. Pat. No. 5,331,602; Anstadt et al., U.S. Pat. No.
4,141,944; Bosler, U.S. Pat. Nos. 5,906,840; 5,314,325, 6,823,794
and 6,641,384; Cameron et al., U.S. Pat. No. 5,053,176; Dorchester
et al., U.S. Pat. Nos. 5,866,054 and 5,869,176; Saloom, U.S. Pat.
No. 5,387,381; and Soda et al., U.S. Pat. No. 3,936,518, which are
hereby incorporated by reference. Most of these disclosures, other
than the Bosler patents, relate to the use of embossing rolls
located immediately downstream of the extrusion die. The embossing
operation is designed to emboss the surface configuration, or
provide ornamentation onto the capstock layer side of a plastic
sheet. The embossing rolls apply tension to the sheet of plastic to
draw the sheet of plastic down to a particular dimension. Following
embossing, the embossed sheet is typically preformed in a die into
a rough version of a siding profile. See, for example, Dorchester
et al. U.S. Pat. No. 5,869,176, at col. 6, lines 11-26. While
siding can be embossed readily with good effect, the high pressure
of embossing rolls is ill suited for hollow profiles, such as fence
boards and hollow decking planks, which would likely collapse under
such pressure.
[0005] Multiple hollow fence board products made of thermoplastic
materials are available in the market. Present hollow, semi-hollow,
thin walled fence boards made of polymer based materials (neat,
composite, or with fillers) made in extrusion processes have a
surface which is smooth or enhanced by longitudinal, machine- or
extrusion-direction texture, lines, ribs, or depressions. Such
products do not have the look of natural wood, such as softer areas
indicative of environmental wear, or harder areas which are
generally more resistant to environmental wear. These hard and soft
areas form peaks and valleys on the natural wood board surface
following natural wood patterns which do not always line up with
the machine- or extrusion-direction of synthetically made
materials. Furthermore, hollow, thin wall fence board products
currently available in the market exhibit a high surface gloss
which reveals the true character of this material, and often make
them undesirable on aesthetic grounds.
[0006] Continuous and semi-continuous processes for creating
patterns on extruded plastic sheets have been used in the building
components industry for a number of years. Some prior systems have
disclosed rigid linked patterns for forming shaped impressions in
an extruded sheet material. Unfortunately, such rigid shaped
patterns tend to form unsightly horizontal seams in the material.
Other systems have used pattern forms on rotating cylindrical
drums. Although these processes are continuous, and do not produce
horizontal seams, they often require expensive additional equipment
and instrumentation to align the arcuate surface of the pattern
with the relatively flat surface of the product, and to avoid, or
correct, unwanted bowing of the product.
[0007] Because of the limitations on prior continuous processes,
some manufacturers have opted for injection or blow molding
building products one at a time. While such techniques can provide
the desired detail in texture and surface finish, they are
generally limited to product sizes of about 4-5 feet in length and
provide product thicknesses which are practically limited to
greater than about 0.080 inches. This is generally because of the
difficulty associated with flowing hot viscous polymer through thin
cross-sectional profiles in steel molds. Additionally, because of
the known size limitations, the randomness of individual features
on the surface of a molded product is limited. This results in only
a relatively small number of pattern elements, such as shingles,
being molded into the relatively small surface area. When several
of these products are aligned side by side on a wall or roof of a
building, for example, it is sometimes obvious to see the pattern
repeated over and over again. Accordingly, there remains a need for
improved vacuum embossing techniques for use in connection with
extruded hollow thin wall profile products.
SUMMARY OF THE INVENTION
[0008] An exterior building product comprises, a polymeric unitary
hollow member having a hollow interior portion and an exterior
portion, and said polymeric unitary hollow member being closed
along all exterior sides. According to an embodiment of the
invention, the exterior sides are unitary with the hollow member,
and are either seamless or pivot along a hinge and latch
together.
[0009] A building product comprises a continuous length pattern of
surface topography features embossed in exterior sides of a hollow
member formed as a unitary extrudate. The invention further
includes a process and apparatus for making the building product,
wherein the exterior sides are supported to resist collapse thereof
while heat and forces are applied during embossing, and the sides
form a hollow unitary extrudate with ribs extending between the
sides. According to an embodiment of the invention the unitary
extrudate comprises a hollow extrudate wherein the interior of the
hollow extrudate is supported by mandrels after extrusion and
during embossing to resist collapse thereof. According to another
embodiment, the extrudate has unitary ribs and is folded to form a
hollow configuration with the ribs interlocked. Further embodiments
of the invention pertain to a method of making a hollow building
product having embossed exterior surface texture elements or
features formed by embossing a continuous length of a hollow
unitary extrudate while supporting the extrudate to resist collapse
thereof while heat and forces are applied during embossing.
[0010] According to another embodiment of the invention, a
continuous length pattern of surface topography features are
embossed in exterior sides of a unitary extrudate, wherein the
exterior sides having the surface topography features embossed
therein are pivotable about a unitary hinge such that the exterior
sides close and form a hollow unitary product. Further embodiments
of the invention pertain to a unitary hollow product having
extruded unitary interior reinforcing ribs. Further embodiments of
the invention pertain to a continuous length pattern of embossed
surface texture elements embossed lengthwise in a unitary product,
wherein the surface texture elements or features are irregular in
recessed depth, raised height and area pattern, to appear as
randomly shaped surface texture elements or features occurring in
respective natural materials. Further embodiments of the invention
pertain to a hollow unitary product having unitary internal
reinforcing ribs and unitary exterior surface topography features
formed by embossing opposite sides of the hollow unitary product.
In an embodiment of the present invention, an exterior building
material is provided which includes a substantially hollow, closed,
thin wall profile comprising a polymeric composition, the profile
including an interior-facing surface portion and an exterior-facing
surface portion. Upon the exterior-facing surface portion of the
profile is presented a low gloss textured pattern disposed
continuously along the exterior-facing surface portion. The low
gloss textured pattern has a gloss level of less than about 50 on a
60.degree. glossmeter, and has at least one cross-machine direction
textured pattern element.
[0011] A further embodiment of the present invention provides an
apparatus and a method of making an exterior building material
comprising extruding a first polymeric composition including an
additive and a colorant through a die to form a polymeric profile
having a substantially closed, hollow shaped form; supporting an
internal surface of said hollow shaped form with a mandrel; vacuum
embossing the polymeric profile on a flexible rotating belt to form
a textured pattern, said textured pattern disposed on an exterior
surface of said polymeric profile; whereby said mandrel supports
said internal surface of the hollow shaped form against a
collapsing force while also assisting in providing a better vacuum
seal. Following the vacuum embossing step, the embossed profile is
calibrated, cooled and cut.
[0012] A further embodiment of the present invention employs a
hollow extrudate supported internally by one or more mandrels, each
preferably a floating mandrel, such as a PTFE or fluorocarbon resin
coated steel mandrel or a unitary PTFE or fluorocarbon mandrel that
is solid or hollow, and which is disposed inside the extruded soft
profile of the extrudate. The preferred floating mandrel is a
rigid, low friction, internal support, which prevents the extruded
shape from collapsing and prevents the rubber or silicone belt from
sagging and breaking its vacuum seal with its underlying perforated
metal belt. The floating mandrel is preferably disposed between the
extruder and the end of the embossing step, more preferably, from
the beginning of the embossing step to about the location of the
vacuum chamber or vacuum boxes. The vacuum boxes can thereafter
assist in keeping the outer wall of the extruder profile and the
silicone belt in close proximity to the perforated metal belt by
vacuum pressure.
[0013] In a further embodiment of the present invention, a
continuous method of making an exterior building material is
provided. The method includes the steps of extruding a first
polymeric composition including adding a colorant through a die to
form a polymeric sheet; vacuum embossing the polymeric sheet on a
flexible, rotating belt to form a low gloss texture pattern of
about 2-20 feet in length, the textured pattern disposed on the
polymeric sheet and having a gloss level of less than about 50, and
more preferably 30 or less, on a 60.degree. glossmeter. The
textured pattern includes at least one textured element disposed in
a cross-machine direction. The process further includes forming the
embossed polymeric sheet into a closed, hollow shaped article;
calibrating the shaped article; cooling the calibrated and shaped
polymeric article; and cutting said cooled and calibrated shaped
polymeric article.
[0014] In still a further embodiment of the present invention, an
exterior building material comprising first and second
substantially hollow polymeric shell portions are joined together
by a hinge and fastened together by fastening means to form a
substantially hollow thin wall polymeric article. The polymeric
article has a low gloss simulated wood grain disposed on an
exterior-facing surface portion thereof.
[0015] In yet another embodiment of the present invention, an
extruded product comprising an elongated member having a first side
comprising a capstock layer; and a second side comprising one or
more male fastening members disposed along one lateral side of said
second side, and one or more female fastening members disposed
along an opposite lateral side of said second side; said polymeric
member being foldable along a central, longitudinal axis so as to
connect corresponding ones of said male and female fastening
members together to form a hollow, closed, thin wall building
material having generally a length of about 2-20 feet. These
male-female connections are made while the polymeric material is
still hot, so as to allow the male and female members to melt-bond
together, or these connections are joined after cooling to form a
mechanical joint or supporting structure.
[0016] In a further embodiment of the invention, a continuous
method of making an exterior building material is provided in which
a first polymeric composition is extruded through a die to form a
polymeric profile having a form selected from the group consisting
of: shells, a substantially closed, hollow shape, and a sheet. The
polymeric profile is then vacuum embossed on a flexible rotating
belt to form a low gloss textured pattern of about 2-20 feet in
length, the textured pattern disposed on said polymeric sheet
having a gloss level of less than about 50 on a 60.degree.
glossmeter, and having at least one textured element disposed in a
cross-machine direction. The embossed, polymeric profile is then
formed, calibrated and cooled prior to cutting the formed, cooled
and calibrated profile.
[0017] The preferred extruded products of this invention have a
hollow, thin wall having a thickness of about 0.005-0.25 inches
(0.127-6.35 mm), preferably, less than about 0.100 inches, and more
preferably, about 0.055-0.080 inches.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings illustrate preferred embodiments
of the invention as well as other information pertinent to the
disclosure in which:
[0019] FIG. 1 is a partial diagrammatic side plan view of a first
apparatus for extruding and continuously vacuum forming a polymeric
material of this invention;
[0020] FIG. 2 is an enlarged view of the extruded polymeric
material following the extrusion step of the apparatus of FIG.
1;
[0021] FIG. 3 is an enlarged view of the embossed polymeric
material as it exits the vacuum embosser of the apparatus of FIG.
1;
[0022] FIG. 3A is a schematic view of a seamless hollow product in
the form of a board having one or more unitary seamless interior
reinforcement ribs;
[0023] FIG. 3B is a schematic view of another seamless hollow
product in the form of a board having one or more unitary seamless
interior reinforcing ribs;
[0024] FIG. 4 is a partial diagrammatic side plan view of a second
apparatus for extruding and continuously vacuum forming the
polymeric material of this invention;
[0025] FIG. 5 is an enlarged view of the extruded material as it
exits the extruder of the apparatus of FIG. 4;
[0026] FIG. 6 is an enlarged view of the embossed polymeric
material as it leaves the vacuum embosser of the apparatus of FIG.
4;
[0027] FIG. 7 is an enlarged view of the folded sheet after it
exits the folding die of the apparatus of FIG. 4;
[0028] FIG. 8 is a cross-sectional view of a semi-finished product
taken through line 8-8 of FIG. 4;
[0029] FIG. 9 is a partial diagrammatic side plan view of a third
apparatus for extruding and continuously vacuum forming the
polymeric material of this invention;
[0030] FIG. 10 is an enlarged view of the extruded material having
a high gloss surface with a grain color following the extrusion
step of the apparatus of FIG. 9;
[0031] FIG. 11 is an enlarged view of the embossed material having
a low gloss, textured surface and grain color following the vacuum
embossing step of the apparatus of FIG. 9;
[0032] FIG. 11A is a schematic view of a seamless hollow product in
the form of a board having one or more unitary seamless interior
reinforcement ribs;
[0033] FIG. 11B is a schematic view of a hollow product similar to
that of FIG. 11A and having a capstock layer.
[0034] FIG. 12 is a partial diagrammatic side plan view of a fourth
apparatus for extruding and continuously vacuum forming the
polymeric material of this invention;
[0035] FIG. 13 is an enlarged view of the semi-finished shaped
article having a low gloss, textured surface and grain decoration
thereon;
[0036] FIG. 14 is a partial cross-sectional fence board of the
present invention showing its hollow profile and alternative
constructions for one or more interlocking internal strengthening
ribs, and textured surface portions pivotally connected along a
hinge, and interlocked along a latch;
[0037] FIG. 14A is a view of a product similar to that of FIG. 14
and further having a capstock layer;
[0038] FIG. 15 is a top plan view of the extrusion, paint
application, and vacuum forming chambers of a fifth preferred
apparatus for vacuum forming polymeric material according to this
invention;
[0039] FIG. 16 is a diagrammatic side plan view of the preferred
vacuum embosser showing a loss of vacuum and product collapse;
and
[0040] FIG. 17 is a diagrammatic side plan view of the vacuum
embosser of FIG. 16 following the introduction of a floating
mandrel.
DETAILED DESCRIPTION OF THE INVENTION
Introduction
[0041] The present invention is designed to make exterior building
materials, such as hollow or semi-hollow (hereinafter just
"hollow") fence boards, decking, window frames, door skins and
ceiling tiles or panels and some siding and roofing products which
have improved natural surfaces, such as surfaces resembling natural
wood, including texture, grain pattern, colorant pattern and low
gloss. The proposed combination of extrusion processing with
embossing, such as, by continuous vacuum embossing processes, is
capable of enhancing product appearance by applying a low gloss
pattern of about 2-20 feet in length in any direction, including a
cross-extrusion or cross-machine direction, to a thin wall product
surface to emulate a natural texture. Furthermore, combining
thermoplastic materials with colorants and streaker pigments, for
example, or a combination of extrusion processes with inline
decorating processes, such as printing, adds grain patterns as a
final requisite of a natural wood appearance. Finally, by producing
building materials having a hollow profile, posts and rails and
fence boards and decking planks are made from polymeric materials
inexpensively, but yet have surface texture, grain pattern and low
gloss resembling natural wood.
[0042] The present invention relates to methods of producing
exterior building materials having substantially hollow
configurations, preferably with shaped profiles and methods of
manufacturing the same. As used herein, the term "embossing" means
a mechanical or chemical process that puts texture into an
otherwise smooth finish. The term "gloss" is a measurement of the
reflection of light off a finished product at a given angle of
incidence and reflection. Sometimes measured using a glossmeter, it
is expressed as a numerical reading. The higher the gloss level,
the shinier the surface. The term "matte" refers to low gloss or an
absence of gloss. Also as used herein, the term "grain" means the
direction, size, arrangement and appearance of fibers or patterns
in a wood-like material, or the simulation thereof. As used herein,
the terms "heat deflection temperature" is the temperature at which
a polymeric material deflects 0.010 in. under a load of 66 or 164
psi, as defined in ASTM test D 648. Also as used herein, the term
"polymeric material" shall mean polymeric compositions which
includes but is not limited to, compositions having, additives,
such as ultra-violet light stabilizers, fillers, plasticizers,
tints, and other additives, such as glass or wood fiber. The term
"molded" means any number of processes, or combinations thereof,
for forming an impression in a polymeric material, including
compression molding, transfer molding, injection molding, blow
molding, autoclave molding, contact molding, pressure bag molding,
vacuum bag molding, deep draw molding, lay-up molding and spray
molding, etc.
Process and Apparatus Introduction
[0043] The preferred method of this invention is best understood by
reference to the FIGS. 1-17, which will now be described. This
method provides a first apparatus 100, FIG. 1, for the continuous
vacuum forming of a hot polymeric material, including a
thermoplastic or thermosetting composition, for example, such as
polyvinyl chloride ("PVC"), polyethylene, polypropylene,
polyurethane, epoxy, polyester, polycarbonate, etc., or other
similar materials. The hot polymeric material, as shown in FIGS. 1,
4, 9 and 12, or the hot polymeric material shown in FIGS. 15-17 is
first extruded from an extruder 20, and is then disposed upon a
flexible rotating belt or vacuum embosser 30 and between a bottom
mold belt 515 and a top mold belt 516, in FIGS. 1, 4, 9, 12, 16 and
17. Each mold belt 516 and 515 of the embosser 30 is suspended, as
shown in FIG. 17, between a first drive roller 520 and a second
idle roller 530 in a substantially horizontal direction. The
embosser 30 preferably contains a porous drive belt 513, 514, FIGS.
16 and 17, to facilitate flexing of its rotating belt and the
passing of air or vacuum pressure. It is most preferably made from
stainless steel mesh or other open forms, such as interlocking
metal or polymer sections, chain link, screen or hinged segments of
corrosion resistant material. Each of the rotating mold belts 515,
516 of the embosser 30 also includes a softer, resilient mold belt
515, 516, one or both containing a mold impression, such as a
continuous length pattern of surface texture elements or features,
such as, a wood grain impression, or a similar impression for
producing a low gloss embossed textured surface, 135, 235 and 335
in FIGS. 3, 6, 11, 13, 14 and 15, respectively. The resilient mold
belt 515, 516 also includes a plurality of apertures therethrough
for passing air, such as an applied vacuum pressure. Such details
of vacuum embossing are further disclosed in Bosler, U.S. Pat. Nos.
5,906,840; 5,314,325, 6,823,794 and 6,641,384.
[0044] The first and second rollers 520, 530 of each flexible
rotating mold belt 516 and 515 of the embosser 30 are spaced apart
from one another in a generally horizontal direction such that the
rotating belt 516, 515 extends between them, and forms a
substantially flat forming surface. The mold belt 516 and 515 is
preferably made of a resilient flexible material such as rubber, or
rubber-like material, such as silicone or synthetic rubber.
[0045] Each mold belt 515 and 516 and corresponding drive belt 513,
514 are frictionally or mechanically engaged so that, by driving
the drive belt 513, 514 with drive axle and drive roller 520, the
corresponding mold belt 515 and 516 moves as well. The mold
impression of the mold belt 516 and 515 substantially retains its
shape as it spins, or stretches slightly, so there is no need for
multiple sections and seams. The continuous mold impression
preferably is a continuous length pattern of surface texture
elements or features on a corresponding continuous mold belt 516
and 515. The continuous mold impression is transferred by being
impressed by continuous vacuum embossing into the opposite sides of
the product 60 in FIGS. 1, 3 and 3A, and the product 60' 3B, the
product 160 in FIGS. 4, 6, 8 and 14, the product 160' in FIG. 14A,
the product 260 in FIGS. 9, 11 and 11A, and the product 260' in
FIG. 11B, and the product 360 in FIGS. 12 and 13.
[0046] In FIG. 17, vacuum boxes 508, 510 cooperate with a plurality
of apertures in the respective mold belts 516 and 515 and the open
spaces in the corresponding drive belt 513, 514 to draw a vacuum
against the bottom surface and the top surface, respectively, of
the extruded hollow profile 575 having the mandrel 31, or
alternatively, as shown in FIGS. 4, 14 and 14A to draw a vacuum
against the open and foldable, extruded profile formed without a
mandrel 31. The mold belts 515 and 516 optionally includes
longitudinal and lateral sections impregnated with polymeric or
resilient rubber-like material which is relatively impervious to
air flow. Such sections are provided with a plurality of vacuum
openings, such as circles, or rectangles, etc., through which air
can pass through and be drawn by vacuum through the open weave
metallic material of the preferred drive belt 513, 514. Preferably
the plurality of apertures defined in the mold belt 516 and 515 are
in open communication with respect to the vacuum sections of the
drive belts 513, 514. This facilitates drawing the hot extruded
profile 575 of the extrudate material by vacuum against the mold
impression, and by a vacuum provided by the vacuum boxes 508, 510.
The hot plastic, while retaining an elevated temperature resulting
from the heat of extrusion so as to remain, at least at, and
preferably above its heat deflection temperature, is drawn onto the
mold impression, and surface texture of fine detail is vacuum
formed by being pressed into a central region of the polymeric
profile 575 of the material. The lateral edge portions of the
polymeric material may or may not be impressed with vacuum formed
surface texture. A suitable support belt and vacuum manifold are
disclosed in U.S. Pat. No. 5,906,840.
[0047] The present invention further relates to creating patterns
such as variegated colors or wood grains on hollow-profile building
materials, for example, decking, fencing posts, rails, boards,
railing, siding and window framing applications, to name a few.
This invention may employ sprayed, painted, coated or printed
capstock layers and top coat layers having a total thickness of
preferably less than 4 mils, and more preferably 1 mil or less,
which have the ability to perform well long term, and have ample
weathering performance, mildew resistance, and dirt repellency,
while simultaneously providing good adherence to thermoplastic
substrates, such as those manufactured with PVC, polyethylene,
polystyrene, polypropylene, either in virgin or recycled form.
[0048] With reference to the Figures, and particularly FIG. 1
thereof, there is shown a first manufacturing process line 100 for
making the building materials of this invention, The manufacturing
process begins as bulk resin is unloaded from railroad cars to a
conveying system, into huge silos holding up to 250,000 pounds or
more of material. From these main storage silos, resin is conveyed
to a blender, where ingredients such as calcium carbonate,
TiO.sub.2 and other additives and micro-ingredients, are added to
create the processing compound. This precise measuring of
ingredients and uniform blending under proper heating conditions
can be important to the production of uniform, high quality
building products.
[0049] After blending, the compound is conveyed to the extruder 20
where it is carefully metered so a consistent amount of material
enters the hopper 10. The extrusion operation is a process in which
thermoplastic resin is pushed through a heated barrel and die by
one or more large, precisely tooled screws. As they turn, the
screws knead and thoroughly mix the thermoplastic compound and
additives such as UV stabilizers, plasticizers, blowing agents,
copolymers, and/or other extrudable thermosetting resins. Both the
screws and the barrel of the extruder are preferably heated which
melts the resin and makes it easier to mix and push. The heat (300
to 400.degree. F. for PVC), also accelerates the physical reaction
(fusion) between resin and the micro-ingredients in the
compound.
[0050] Most building products, such as siding, are extruded with
twin-screw extruders. Twin-screw extrusion is preferable to
single-screw extrusion because it heats and distributes material
more evenly, resulting in a product with better physical
properties. As the resin compound is forced ahead of the rotating
screws, the very tight tolerances in the double barrel promote
complete fusion of the ingredients. Color concentrate is added at
the extruder, which helps to produce a rich, durable, all the way
through color, in each exterior building product.
[0051] Co-extrusion, is used to join two flows of molten resin
compound from two extruders 20 and 70 in a single die to produce an
extrudate of a single polymeric sheet comprising two layers of
materials, such as a substrate and a "capstock layer." As used
herein, the term "capstock layer" refers to a thin protective layer
added to some exterior building products to improve weatherability
and color retention. The capstock layer comprises either a single
layer of polymeric material, or comprises a multilayer having two
or more polymeric layers, each of which is extruded one over the
other, either by coextrusion in a single extruder, or by separate
extrusion in a number of successive extruders. The one or more
layers comprising the capstock layer are unfoamed and are
preferably nonporous and selected to provide a visually aesthetic,
finished surface and which comprise polymer compatible additives
imparting chemical and mechanical properties, for example, water
and moisture resistance, flame resistance, ultraviolet resistance,
surface texture or finish, colorfastness, toughness, solar
reflectance, wear resistance, impact resistance and stain
resistance. In an embodiment of the invention, one or more layers
of a multilayer capstock layer comprises a matrix of translucent
resin or transparent polycarbonate for example, and an alternative
embodiment of an accent color streakers of polymeric colorant in
opaque and transparent or translucent layers comprising the
capstock layer. Typically, the capstock layer material comprises
acrylic-containing resin, such as AES, ASA, or alternatively,
polyethylene or polypropylene. Capstock layer co-extrusion requires
a processing window due to the difference in coefficient of linear
thermal expansion rates between the capstock layer and base or
substrate. Missing this window often leads to unacceptable
dimensional distortion or bowing of the panel, lineal, lintel or
framing member, fence or board, for example.
[0052] In FIGS. 1 and 17, as the extrudate exits the extruder 20,
the polymeric sheet or profile 575 is still very hot, nearly
molten, and has a glossy or smooth extruded appearance 25 of its
surface as shown in FIG. 2 (e.g., over 50 gloss reading on a
60.degree. glossmeter measuring reflection at a 60 degree angle).
The gloss of the surface will have slight manufacturing
imperfections, such as scratches and faint lengthwise straight
lines imparted to the product by slight surface imperfections in
the extrusion die. Such slight imperfections detract from the
appearance of the surface, and leads to rejection of pieces of the
products, which differ in gloss when compared against one another
or which are not perfect in terms of gloss appearance. Although the
extrusion process enables manufacture of straight grooves of
constant width and depth or raised ridges of constant width and
height, such does not duplicate the random surface features
appearing on natural materials, i.e. materials occurring in nature.
According to an embodiment of the invention, between the extruder
20 and the calibration die 40 is located the mold belts 516 and 515
of the vacuum embosser 30 (collectively, vacuum embossing apparatus
or step). Depending on the rollers or belts, fencing, and decking,
products and accessories are typically embossed in either rough
cedar, wood grain or smooth or brushed low gloss surface finishes
that look like raised grain wood, rough hewn or split wood, or
sanded, sealed and painted wood. For example, natural wood fence
boards are kiln dried or air dried over time and further are worn
by the weather, all of which contribute to the wood surface
becoming a random or irregular pattern of striations of recessed
soft wood grain, and striations of harder wood grain that appear to
be raised relative to the soft wood grain striations. Painted fence
boards further have such striations covered with fresh paint, which
are simulated by an embodiment of the invention, as described with
reference to FIGS. 3 and 3B. Hewn or split wood fence boards have
further surface texture elements or features that are indicative of
hewn or split rough wood surfaces, as described with reference to
FIGS. 3, 3A, 14 and 14A. Some wood varieties, such as split cedar
and Douglas fir have rough checks in the wood surface that reappear
over time, after being sanded smooth or painted. Usually, such wood
surfaces are unsanded and unpainted, since the rough surface checks
reappear as defects in a sanded or painted surface. For example,
FIG. 3A discloses embossed surface texture 135, which comprises
embossed surface texture elements or features, which are irregular
in recessed depth, raised height and area pattern, to appear as
randomly shaped surface texture elements or features occurring in
respective natural materials. FIG. 3A illustrates an extruded and
embossed product 60 in the absence of a capstock layer having an
embossed surface texture 135 simulating an unpainted low gloss
textured rough wood surface, produced by the embosser 30. FIG. 11A
discloses similar surface texture 235, as well as, streaker grain
color 237. FIG. 3B illustrates an extruded and embossed product 60'
in the absence of a capstock layer having an embossed surface
texture 135 simulating a low gloss textured wood grain pattern
having raised and recessed wood grain striations that simulate
unpainted or painted surfaces depending upon the color, such as,
wood color or paint color thereof. Another advantage results from
the embossing process to reconfigure the gloss of surface 25 and
the surface defects produced by the extrusion process by embossing
the same to form a matte or low gloss surface texture 135. Further,
U.S. Pat. No. 6,752,941 discloses the addition of accent color
pellets and a streaker concentrate, which is added to the hopper 10
to produce a dispersion of accent color in an extruded product. For
example, FIG. 11A discloses a product 260, in the absence of a
capstock layer and having the embossed surface texture 235 and the
accent color in the form of a colorant streaker pattern of grain
color 237 produced by the extruder 20. Further, for example, FIG.
14 discloses a product 160, respectively, in the absence of a
capstock layer having the embossed surface texture 135 and a
colorant streaker pattern of grain color 137. FIG. 14A discloses a
product 160' having a capstock layer 138 and the embossed surface
texture 135 and a colorant streaker pattern of grain color 137 in
the capstock layer 138.
[0053] Some building products 60, 60', 160, 160', 260, 260' and 360
are treated with a post-forming step or steps. Equipment, such as
vacuum sizers of the calibration die 40 and post-formers, provide
greater consistency in post-formed thickness and profile.
Post-formed locking devices in siding, for example, disclosed by
U.S. Pat. Nos. 6,319,456 and 6,737,008, comprise tighter tolerances
and more intricate interlocking structures, which result in higher
wind load ratings. Post-forming operations further include the
calibration dies 40 including but not limited to, pre-sizers and
vacuum sizers and shaping dies (collectively, 40) prior to the
cooling tank 50 to create distinctive profiles and a wide range of
sizes for products 60, 60', 160, 160', 260, 260' and 360. In a
vacuum sizer as the calibration die 40, the product is given a
crisp finish profile. In FIG. 3B, tongue and groove edges along
opposite side edges of a simulated board 60' are heated at least to
its heat deflection temperature, alternatively, at least to its
vicat softening point temperature, sized and straightened in the
calibration dies 40, for example, to obtain accurate dimensions of
tongue and groove joint sections that interengage when a number of
simulated boards 60' are installed side by side and interlocked by
tongue and groove joints, for example, to construct a fence or a
deck. Alternatively, the opposite side edges 166, 169 of a
simulated board 160 or 160' are heated at least to its heat
deflection temperature, alternatively, at least to its vicat
softening point temperature, sized and straightened in the
calibration dies 40, for example, to obtain accurate dimensions and
to melt bond the joint 166.
[0054] The cooling tank 50 is located after any post-forming
operation. Once the hot sheet, including an optional, i.e.
alternative embodiment of, a painted and/or printed layer over the
polymeric substrate, is introduced into the cooling tank 50, the
product temperature quickly drops below its "heat deflection
temperature" and the final shape sets. An embodiment of the
invention comprises a gravure roll coater or other form of a
printer 311, FIG. 12, located between the vacuum embosser 30 and
the cooling tank 50. The painted and/or printed layer dries
separately from the cooling tank 50 when painted and/or printed
either before or after the hot sheet is cooled in the cooling tank
50.
[0055] A coating step comprises printing by a gravure roll coater
("print roll") comprising an exemplary embodiment of the printer
311, 312 or 313, FIG. 12, which are provided and located before or
after the embossing step by the vacuum embosser 30, or before or
after the vacuum sizer of the calibration die 40, for example.
Preferably the capstock layer coating step occurs prior to water
cooling by the cooling tank 50, so that the substrate's heat of
extrusion is used to dry the capstock layer coating. In another
preferred embodiment, the coating step comprises printing patterns
of colors by one or more computer controlled ink-jet printers 311,
312 or 313, FIG. 12, that performs depositing one or more print
layers in succession, such as a 100% opaque capstock layer followed
by depositing print layers comprising one, two or three variegated
layers that dry prior to water cooling.
[0056] After passing through the cooling tank 50, the substrate and
alternative embodiments of a painted or printed layers and/or
alternative embodiments of a capstock layer are optionally punched
with openings, not shown, at precise intervals for insertion of
metal supporting rods, nails or fasteners and the like. Finally,
the product 60 is cut to length at cut off, inspected and
packaged.
Variegated Surfaces and Decoration
[0057] The embodiments of the invention comprise one or more
spraying, painting, and/or printing steps ("coating step")
disclosed in FIG. 12, for example, which follow the extrusion step
or following the alternative embodiment of a co-extrusion step to
form both a capstock layer and one or more top coat layers that
provide a variegated pattern, textured and with or without a
colored pattern, to the alternative building material product 60,
60', 160, 160', 260, 260' and 360. The variegated textured pattern
comprises a wood grain in one or more coating layers. The coating
step includes but is not limited to, hot painting, thermal
spraying, paint spraying, fusion coating, inkjet printing and
gravure roll coating, for example. A gravure roll coater 311, FIG.
12, is located between the vacuum embosser 30 and the cooling tank
50 in the preferred manufacturing schematic of FIG. 1 to perform
the coating step.
[0058] The inks, pigments, coatings or paints create variegated
wood grains and colors applied by direct printing or coating, for
example, is provided without collapsing distortion or bending of
thin panels, long decking planks, or intricate window lineal,
lintel or framing member, fences. Preferably, the total coating
thickness will be less than 4 mils, and preferably, 1 mil or less,
compared to existing co-extruded ASA capstock layers of about 4-6
mils, used in PVC siding, for example.
[0059] While various coatings are employed in connection with
variegated surfaces of this invention, those including PVC,
polyethylene, polypropylene, ASA and other acrylic-based
compositions and fluorocarbon resins, such as,
polytetrafluorethylene, PTFE, PFA, ETFE, ECTFE, FEP, polyvinylidene
fluoride, PVDF, PPS, EFEP, TEFLON.RTM., and other thermoplastic or
thermosetting resins, are desirable. These compositions are applied
to thermoplastic or thermosetting sheets or construction materials
by such techniques as thermal spraying, paint spraying, fusion
coatings, inkjet printing, and gravure roll printing, for
example.
[0060] One method for making the capstock layer and the first,
second, and subsequent top coat layers of the variegated building
products of this invention, employs a water base emulsion ink or
paint containing a copolymer of PVDF and Hexa Fluoro PVDF that is
polymerized in the presence of an acrylic component. The preferred
coating is sold under the trademark Kynar.RTM. and is provided by
Arkema.
[0061] The hollow building product of this invention also relates
to an article that has a variegated effect appearance. The article
comprises a mixture of a substantially non-opaque (i.e., neither
transparent nor translucent) polymer matrix, and color particles
having different melt flow properties from the polymer matrix. The
initially discrete color particles are suspended in the non-opaque
matrix, and streak out during processing, acting as accent color
pellets or masses. By "streak out" is meant that the color
particles extend and form variegated lines and shades of color for
example the colorant streaker pattern of grain color or grain
indicia 137. The transparency or translucency of the non-opaque
matrix adds a depth or dimension to the variegated appearance. For
exterior applications, at least the outermost layer, which would be
exposed to the environment, is protected by appropriate
antioxidants, thermal stabilizers, photostabilizers, etc.
[0062] The melt index (MI) of a polymer resin is a measurement of
processability under low shear rate conditions, The MI is
determined by ASTM D-1238 (for example, Condition E for PVC)
(190.degree. C./2.16 kg). For instance, the MI of the polyolefins
is generally between about 0.2 dg/min, and about 100 dg/min,
preferably, between about 1 dg/min and about 10 dg/min, and most
preferably, between about 2 dg/min and about 8 dg/min. The MI of
the polymer resins are measured using ASTM D-1238.
[0063] When thermoplastic materials are heated, the thermoplastic
begins to soften, its physical properties changing in various ways.
The temperature at which a measurable softening of the
thermoplastic occurs when heated is, preferably, measured by the
"vicat" method, and is referred to as the "vicat softening point
temperature". Analogous or related temperatures are measured by
other methods, resulting in other scales of temperature versus
physical property, such as the heat deflection temperature, or the
melt flow index. The vicat method and scale, preferred by the
present inventors, is specified by ASTM-D-1525, from which the
vicat softening point temperature referenced herein was obtained.
The vicat softening point temperature indicates the softening
temperature at which the resin begins to melt in response to
increased temperature. The melt flow index is a measure of the
viscosity of a resin when it has fully melted.
[0064] The transparent matrix material includes either a plurality
of types of color particles and/or accent color pellets. The
variations in color particle type include different colors of
pellets, different sizes of pellets, different melt flow behavior
of pellets, or pellets having different relative viscosities
compared to the matrix polymer. The different colors will result in
different sizes or shapes of streaks. The different viscosities
will result in different lengths of streaks. The different kinds of
pellets contribute to the complexity of the variegation obtainable
with this invention, and to the aesthetics of simulation of a wood
grain or a mineralogical veining effect for the finished article.
Methods whereby the formation of the article are accomplished
include for example, extrusion, molding, and injection molding.
[0065] Furthermore, an article made by the processes of the present
invention alternatively comprises a plurality of variegation layers
wherein each of the layers includes a transparent or
semi-transparent matrix, and one or more kinds of accent color
particles. The layers are formed, for example, by extrusion of
individual layers followed by lamination or bonding to construct a
multilayer article. Alternatively, the various layers are
coextruded through, for example, a plural manifold die system to
form the multilayer article in fewer steps. The articles of the
present invention are provided with a transparent or translucent
protective overlayer or capstock layer, by means of such as
lamination, coextrusion or coating applications. The coating step
includes but is not limited to, hot painting, thermal spraying,
paint spraying, fusion coating, inkjet printing and gravure roll
coating, for example. The article also includes a colored base
layer, which color is at least partially visible through the
non-opaque, transparent or translucent, matrix of the
streaker-containing layer.
[0066] Different types of color particles include, for example,
color, size and melt rheology. Different sizes will result in
different widths or shapes of color streaks. Different melt
rheology or viscosity during processing will yield different
behaviors in streak flow. For example, lower viscosity streaker
particles will stretch out more on processing. Larger particles
produce wider streaks of variegation. Color particles with greater
miscibility/compatibility with the matrix polymer will produce
streaks having more diffuse boundaries.
[0067] The materials of this invention comprises various
transparent or translucent matrices which are the same or different
chemical families. The layers are selected for controlling other
functionality required in the end product. The rheology of each
transparent or translucent matrix are balanced for the given color
particles contained therein. Each layer provides other
functionality, such as, for example, stabilization and UV
protection in the outer layers, chemical resistance, or resistance
to dirt pickup.
[0068] An alternative embodiment of a transparent matrix comprises
a transparent colorant. This transparent colorant could be a dye or
a small particle pigment. The use of transparent color of a layer
containing a transparent colorant provides a degree of freedom in
imparting a desirable depth in appearance to the article. Also, a
single color particle type is used in each transparent matrix, or a
given layer comprises more than one kind of color particle.
[0069] The colored base or substrate layer comprises any material
desired in making the article of the invention. For example, it
comprises a filled base polymer of less weatherable materials that
are protected by the upper layers which also contribute to a
desirable aesthetic. An embodiment of the base or substrate itself
comprises a plurality of layers. In one instance, it comprises a
colored surface layer adjacent to the variegation layers, with a
layer containing fillers beneath. The base or substrate layers
contribute substantially to the bulk mechanical properties of the
article, while the variegation layers provide a desirable
appearance.
Processes and Apparatus Details
[0070] In a first embodiment of the present invention, a continuous
length hollow extrudate 60 or 60', FIG. 3A or FIG. 3B, with a
hollow, closed thin wall profile is extruded by extruder 20, shown
in FIG. 1. A smooth, extruded glossy outer surface 25, FIG. 2, of
this hollow, continuous cross-section piece exits the die of the
extruder 20. The extrudate profile is a hollow, closed thin wall
profile in the absence of a capstock layer, which includes a
thermoplastic material with additives for weatherability,
durability, flame resistance and other desirable features for an
exterior product. The die of the extruder 20 is equipped with
interior pins or mandrels which are capable of forming the
extrudate 60 or 60' with hollow lengthwise sections separated by
continuous length, unitary internal ribs 162, FIG. 3A or 3B, within
the hollow thin wall extrudate 60 or 60', the ribs 162 bridging
between opposite interior lateral sides of the hollow thin wall
extrudate 60 or 60' to support and resist collapsing forces, and to
support and resist sagging from gravity before vacuum embossing.
Floating mandrels 31 outside of the die are connected to the pins
and mandrels inside the die by corresponding flexible, adjustable
links or connections 526, FIG. 17, such as braided steel wire,
chain, cable or rope, for example, such that the mandrels 31 float
at the ends of the links or connections 526 and remain inside
corresponding interior sections of the extrudate. The corresponding
one or more low friction (e.g., cast, molded or machined unitary
PTFE or other fluoropolymers or metal coated with low friction PTFE
resin or other fluoropolymers) mandrels 31, FIGS. 1, 9, 12 and 17,
keep the hollow extrudate from collapsing under the applied heat
and forces during vacuum embossing opposite sides of the hollow
extrudate by the top mold belt 516 and by the bottom mold belt 515.
Each floating mandrel 31 preferably extends within the vacuum
embosser 30, preferably at least up through the leading edge of the
vacuum boxes 508, 510. (Alternatively, the floating mandrel 31
could be used with a conventional roll embosser.) The floating
mandrels 31, FIGS. 1, 9, 12 and 17, are surrounded by the interior
surfaces of the respective hollow extrudate sections of the hollow
extrudate 60' while the material is conveyed between the top mold
belt 516 and bottom mold belt 515 of the vacuum embosser 30. The
hollow extrudate sections slide over the low friction mandrels 31
while being transported through the embosser 30. The smooth profile
extrudate from the extruder 20 undergoes embossing in the vacuum
embosser 30, having one or more continuous rubbery mold belts
comprising the lower mold belt 515 and the upper mold belt 516
where applicable, embossing a continuous patterned impression of
controlled, low-gloss, pattern texture 135, 235, 335 in one or more
sides (opposite sides) of the extrudate 60 or 60' having a hollow,
closed thin wall profile of continuous length, and then cut to
desired lengths of about 2-20 feet after emerging from a cooling
tank 50. The preferred extruded products of this invention have a
hollow, thin wall having a thickness of about 0.005-0.25 inches
(0.127-6.35 mm), preferably, less than about 0.100 inches, and more
preferably, about 0.070-0.090 inches.
[0071] Thin wall hollow profiles remain hot and soft during vacuum
embossing. The upper silicone belt 516 of the vacuum embosser 30 is
relatively heavy and tends to sag into the soft hollow profile,
which is too thin to support the weight of the sagging silicone
belt 516. This causes the top wall of the profile to collapse.
This, in turn, creates a gap "a" between the silicone belt 516 and
the perforated belt 514, releasing the vacuum. The result is poor
product quality.
[0072] As shown in FIG. 16, without a mandrel to support the soft
hollow extrudate, the thin wall of the profile 575, which is often
less than 0.010 inches in thickness, can not support the weight of
the upper silicone belt 516, and becomes vulnerable to the
collapsing force of the effect of gravity on the upper belt 516.
This can be demonstrated by looking at the internal cross-sectional
dimension "c" of the profile defined along its inner edge. As the
profile 575 is extruded, it has an internal dimension "c". Upon
entering the vacuum embosser 30, the weight of the upper mold belt
516 is exerted on the upper wall of the profile 575, bending it
downward to reduce the internal dimension to a smaller opening "b",
which results in an unintentional distortion of the building
product. Without support, the upper belt 516 tends to droop,
causing a gap "a" to form between the resilient mold belt 516 and
the porous drive belt 514. This gap "a" results in vacuum from the
vacuum box 510 not being maintained. The loss of vacuum causes the
perforated belt 514 to at least partially lose frictional contact
with the silicone resilient belt 516. In addition, the weight of
the resilient belt 516 is now fully on the thin wall soft profile
575, which results in its distortion. The loss of vacuum pressure
also prevents the outer surface of the thin wall soft profile 575
from being impressed into the texture of the mold or resilient belt
516, which further results in a complete or partial loss of
embossing pressure, and little or no resulting pattern. It also
becomes difficult for the drive belt 514 to continue to
frictionally drive the mold belt 516.
[0073] As shown in FIG. 17, floating mandrel 31 with its preferred
PTFE coating on metal or unitary member of PTFE has a flexible
connection 526 to the fixed mandrel in the extrusion die, which has
been shown to overcome the problems of lost vacuum and distortion
of the formed hollow profile. By assisting in keeping the hollow
profile 575 from collapsing and by maintaining cross-sectional
dimension "c" from the beginning to the end of the vacuum embossing
step, the floating mandrel 31 assists in maintaining the quality of
the extruded profile 575 in both its internal dimensions and its
external textural surface. The floating mandrel 31 not only
maintains the internal dimension of the profile 575, but also helps
maintain the exterior wall of the profile 575 in close contact with
the resilient mold belt 516 to insure that an embossed texture is
made. Artificially supporting the interior of the extruded profile
575 also helps to maintain a vacuum seal between the resilient
belts 515, 516 and the perforated belts 513, 514. Although the
floating mandrel 31 is shown extending across the length of the
vacuum boxes 508, 510, it preferably extends to at least the
beginning of the vacuum boxes 508, 510 or to about line "d". This
position will allow the vacuum boxes 508, 510 to maintain
sufficient vacuum to keep the thin wall profile 575 and the
resilient molding belt 516 in close proximity as they approach the
vacuum box 510, even though a floating mandrel surface may or may
not be provided beyond the edge of the vacuum box 510.
[0074] The surface texture elements or features 135, 235, 335 are
irregular in recessed depth, raised height and area pattern having
a dimension that varies in the cross-machine direction laterally of
the continuous length, to appear as randomly shaped surface texture
elements or features occurring in respective natural materials
compared to a process of extrusion that is limited to producing
straight length dimensions and constant cross sectional dimensions
such as a straight groove of constant depth or a raised straight
rib of constant height. The textured surfaces have a gloss level of
less than about 50 on a 60.degree. glossmeter, and the texture
pattern has at least one texture pattern element with a dimension
that varies in a cross-machine direction relative to the machine
direction of the extrudate formed by extrusion. Following
embossing, the embossed sides and thin wall profile of the embossed
extrudate are subject to a calibration die 40 including but not
limited to, a vacuum sizer or shaping die (collectively 40), or a
combination thereof. Following sizing or other calibration, the
embossed extrudate is then cooled in a cooling tank 50, and emerges
as a finished product 60, 60', 160, 160', 260, 260' and 360,
respectively. The vacuum embosser 30 provides the hollow profile
with a low gloss, textured surface 135, 235 and 335, respectively,
which comprises a pattern of surface texture features, wherein the
surface texture elements or features are irregular in recessed
depth, raised height and area pattern, to appear as randomly shaped
surface texture elements or features occurring in respective
natural materials, for example, a wood grain pattern, FIGS. 3A, 3B,
11, 11A and 14.
[0075] FIG. 4 discloses a second embodiment of an apparatus 200 for
extruding and vacuum embossing a low gloss surface texture 135,
FIG. 6, into one or more exterior surfaces of a hollow product 160,
FIG. 14, that would be susceptible to collapse or bending by the
heat and forces required for vacuum embossing. Thermoplastic
material additives and colorants are disposed in the hopper 10,
followed by extruding through the extruder 20. Following extrusion
at the extruder 20, an extruded sheet extrudate is formed with a
thin wall profile having a first interior major surface on an
interior of the thin wall profile, and a second exterior major
surface on an exterior of the thin wall profile. The extruded sheet
extrudate has a unitary continuous lengthwise hinge folding 169
pivotally joining a first lateral side and a second lateral side of
the extruded sheet. The hinge 169 is formed preferably by extrusion
in the extruder 20 or, alternatively, by embossing in the vacuum
embosser 30. The extrudate comprises the hollow product 160, FIG.
14, in an open and flat configuration prior to being folded along
the hinge 169 to form a hollow closed configuration. The flat
configuration is supported by the upper mold belt 516 against
collapse thereof while the lower belt mold 515 embosses the
exterior major surface of the extrudate with the pattern of
embossed texture 135. A plurality of single ribs 162, FIGS. 4, 5,
8, 14 and 14a, extend continuously lengthwise and project outward
and disposed on the first lateral side formed preferably by
extrusion in the extruder 20 or alternatively formed by embossing
in the top mold belt 516 of the vacuum embosser 30 and formed
unitary with the first major surface, and a plurality of double
ribs 164 extend continuously lengthwise and project outward and
disposed on the second lateral side formed preferably by extrusion
in the extruder 20 or by embossing in the top mold belt 516 of the
vacuum embosser 30 and formed unitary with the same first major
surface. The impression pattern in the mold belt 516 in FIG. 4
differs from the impression pattern of surface texture in the mold
belt 516 in FIGS. 1, 9, 12 and 17, such that the mold belt 516 in
FIG. 2 is shaped to conform to the shape of the ribs 162 and 164,
instead of being shaped with an embossed texture 135, 235 or 335.
FIGS. 14 and 14A disclose various alternative constructions of the
single ribs 162 and of the double ribs 164. Continuous lengthwise
frictional interengagement 161 of an exemplary extruded or
embossed, straight shaped rib 162 with and between a set of two
extruded or embossed straight shaped ribs 164 is disclosed.
Continuous lengthwise latched interengagement 167 occurs between an
exemplary rib 162 having lengthwise unitary V-shaped latches
extruded on opposite sides, and complementary lengthwise V-shaped
latches extruded on respective exemplary ribs 164. Alternatively
each set of the double ribs 165 is modified by having a single rib
164 with a V-shaped latch to interengage with the V-shaped latch of
a corresponding rib 162. A continuous lengthwise adhesive bond or a
melt bond interengagement 163 of an exemplary extruded or embossed
shaped rib 162 with and between a set of two extruded or embossed
straight shaped ribs 164 is disclosed. An embodiment of an adhesive
bond is formed by adding a hot melt adhesive. An embodiment of a
melt bond results from heating the ribs 162 and 164 at their
interface by an ultrasonic welding apparatus. As long as means for
retaining the extruded embossed profile of the sheet into a folded
closed hollow profile product 160 once folded and joined, the
exemplary single ribs 162 interengaging corresponding sets of two
exemplary ribs 164 take on any number of forms, including latched
interengagement, an adhesive bond or a melt bond. Alternatively, a
single rib 164 is substituted for each set of the double ribs 64 to
interengage a corresponding rib 162. The set of interengaging ribs
162 and 164 closest to the hinge 169 is the first to be
interengaged and interlocked, or heated or melted and thereby
interlocked, followed, in turn, by each set that is progressively
farther from the hinge 169 than a previously interengaged set,
while in the process of pivoting lateral sides toward each other
about the folding hinge 169 to fold the extruded embossed profile
of the sheet from an open configuration to a closed
configuration.
[0076] In FIGS. 4 and 9 another extruder 70 of an alternative
embodiment of the invention provides by co-extrusion, a second
polymer composition to form an extruded capstock layer 138 in FIG.
14A and 238 in FIG. 11B. A colorant, such as a streaker material is
added in the hopper 10' of the extruder 70 for adding streaks of
accent grain color 137 and 237, respectively, as disclosed further
by U.S. Pat. No. 6,752,941. Alternatively, the grain color 137 and
237, respectively, comprises streaker colorants in the extrudate
formed by the extruder 20 in the absence of a capstock layer 138 or
238, or alternatively, solely in the extrudate under the capstock
layer 138 or 238, or alternatively, solely in the capstock layer
138 or 238, or further alternatively, in both the extrudate under
the capstock layer 138 or 238 and in the capstock layer 138 or 238.
The streaker colorants in the capstock layer 138 or 238 when
present comprise the entirety of the grain color 137 or 237 or,
alternatively, supplement the portion of the grain color 137 or 237
under the capstock layer 138 or 238 to add grain depth and color
shades to the grain color 137 or 237. Due to co-extrusion and
following such co-extrusion, the capstock layer 138 or 238 is
bonded to the exterior second major surface of the extrudate formed
by the extruder 20 and opposite the interior first major surface
comprising the single rib 162 and the single or double ribs 164.
The external second major surface on the capstock layer 138 or 238,
or the extruded profile in the absence of a capstock layer, is then
subject to an in-line, continuous embossing step at vacuum embosser
30, the bottom belt 515 of which provides an embossed surface
texture, preferably, on the capstock layer 138 or 238 or,
alternatively on the second major surface of the extruded profile
of the sheet, as disclosed by FIGS. 3A, 11A and 14 in the absence
of a capstock layer 138 or 238.
[0077] The capstock 138 or 238 provides a weather durable layer
covering and protecting the core or base material of the vacuum
molded product. An advantage results from vacuum molding the
surface topography recesses 135 in the weather durable capstock 138
or 238 compared to etching, stamping or abrading to remove capstock
material. The vacuum molded capstock 138 or 238 retains its desired
thickness under each surface topography recess 135 formed by vacuum
molding to maximize the thickness of the weather durable
protection. The less viscous core or base material flows to become
thinner. Thereby, the vacuum formed capstock 138 or 238 has a
maximized thickness of weather durable protection, compared to
etching, stamping or abrading to remove capstock material, which
reduces the thickness and the useful life of the weather durable
protection.
[0078] The extruded embossed profile of the folded sheet, FIGS. 14
and 14A, is conveyed through a set of folding dies 175, or similar
equipment, which folds the extruded embossed profile of the sheet
along the hinge 169 into a folded sheet 180, FIGS. 8, 14 and 14A,
of a closed hollow product 160, 160' having a hollow profile and
with the embossed second major surface on the extrudate or on the
alternative embossed capstock layer 138 or 238 on the extrudate
facing outward and comprising multiple exterior embossed sides of
the closed hollow product 160, 160'. In FIG. 4, the folding dies
175, or joining device 177, or both, are used to join the single
rib 162 with the single or double ribs 164 and form a continuous
lengthwise joint 166, for example, a continuous tongue and groove
joint 166, with the continuous tongue formed on one lengthwise edge
of the extruded embossed profile of the sheet and the continuous
groove formed on an opposite lengthwise edge of the extruded
embossed profile of the sheet. The folding dies 175 fold the
extruded embossed profile of the sheet along the hinge 169, while
the joining device 177 applies hot melt adhesive, or heat to melt
the lengthwise continuous surfaces of the ribs 162 and 164 such
that when the hollow profile is completely closed an adhesive bond
or melt bond is formed therebetween, followed by complete folding
and closing of the hollow profile causing the tongue and groove of
the interlocking joint 166 to interengage and latch the hollow
profile in a closed configuration. The joining device 177 further
applies hot melt adhesive or melts the tongue and groove joint 166
to form and adhesive bond or melt bond. Alternatively, the
frictional interengagement or latched interengagement and retention
of the ribs 162 and 164 occur while the hollow profile is folded
and closed. This is followed by calibration, sizing, or shaping by
operation of calibration dies 40, and finally, a cooling tank
50.
[0079] The finished product 160, 160' has a closed hollow profile,
shown in FIGS. 8, 14 and 14A, in which the single rib 162,
alternatively the single rib 162 joined to respective double ribs
164 by being mechanically joined or melt bonded, for example, to
the double ribs 164, to form preferred reinforcing supporting rib
structures bridging across the hollow interior from one lateral
side of the interior surface to the other lateral side of the
interior surface, The product 160, 160' preferably includes a
tongue and groove, glued, mechanical or melt bond joint 166 used to
clasp or retain the hollow profile into a closed structure, as well
as a preferred hinge element 169 which allows the first and second
shell portions or lateral sides of the structure to be pivoted or
rotated about the hinge 169 and interengage or clasped to form the
joint 166.
[0080] The preferred capstock layer, 138 or 238 or, alternatively,
the exterior second major surface of the product 60, 160 or 260 in
the absence of the capstock layer 138 or 238, includes streaks of a
grain color 137 or 237 and embossed texture 135 or 235, as
substantially shown in FIGS. 3A, 8, 11, 11A, 11B, 14 and 14A.
Depending on the temperature of the polymeric material at the
folding die 175 and joining device 177, the joint 166 comprises a
mechanical connection or melt bond connection, and the connection
between the single ribs 162 and double ribs 164 comprises a
mechanical or melt bond, or some combination thereof. Similarly,
the hinge 169 comprises, for example, a softened portion of the
sheet, due to its elevated temperature at this stage of the
process.
[0081] With reference to FIG. 9, there is shown a third apparatus
300 for extruding and vacuum forming polymeric material pursuant to
this invention. This process employs an extruder 20 as in FIG. 1,
and an alternative process comprises an extruder 70 which forms a
coextruded capstock layer 238 in FIG. 11B in which the capstock
layer 238 comprises the surface topography recesses 235 and the
color enhancing wood grain such as the pattern of grain color 237.
Following the co-extrusion operation, the extrudate has a high
gloss surface 238 and the grain color 237 in FIG. 10. In this
embodiment, the extrudate has a closed thin wall profile 260 in
FIG. 11A without a capstock layer, or profile 260' with the
capstock layer 238, FIG. 11B, and colorant enhancing wood grain 237
for providing the final effect of a wood appearance, including
grain color 237 and low gloss texture 235. The grain color 237
comprises streaker colorants in the extrudate, FIG. 11A, in the
absence of a capstock layer or alternatively in either the
extrudate under the capstock layer 238 or the capstock layer 238,
or further alternatively, in both the extrudate under the capstock
layer and the capstock layer 238 to provide differences in grain
color and differences in depth of grain color beneath the capstock
layer 238.
[0082] The die of the extruder 20 is capable of converging the base
thermoplastic for the substrate with a second thermoplastic
material from the extruder 70 creating an outer layer or capstock
layer 238 on the top of the first plastic material. This die of the
extruder 20 has a low friction, floating mandrel or mandrels 31 so
as to maintain a thin wall "hollow" product 260 or 260' with
unitary internal ribs 162 similar to that of the product 60, FIG.
3A, produced by the process of FIG. 1. The floating mandrel or
mandrels 31 are used to support the profile interior to resist
collapse thereof during the vacuum embossing step. Second, third or
more thermoplastic materials in the extrudate preferably have
colorants, such as dyes, pigments and inks, etc., which create a
wood grain color 237 appearance for example. The hollow profile is
then subject to a vacuum embosser 30 with one or more rubbery belts
to create an embossed surface texture 237, such as a wood texture,
on one or more sides of the final product 260 or 260', followed by
the application of vacuum sizing, calibrating or shaping steps by
calibration die 40 and a cooling tank 50 to produce a final product
260 or 260'.
[0083] As shown in FIG. 12, a fourth apparatus 400 for extruding
and continuously vacuum forming a polymeric material is provided.
In this apparatus 400, alternative "decorating" step(s), such as
printing, to enhance wood-like appearances, create a wood grain on
thin wall profiles by operation of printing techniques, preferably,
gravure printing, roll printing, jet printing, water transfer
printing, or hot foil transfer printing. As in the earlier
apparatus, thermoplastic material, additives and colorants are
disposed in pellet form into the hopper 10. The hopper 10 and
extruder 20 is provided. An alternative embodiment comprises the
extruder 70 and hopper 10' for a capstock layer 238. When a hollow
profile is desired, low friction, floating mandrels 31 are used as
in earlier embodiments. In an alternative embodiment a hot paint
applicator, sprayer or printer 310 or 410, FIG. 15 or 12, performs
in-line decorating by applying a painted wood grain to supplement
or increase the wood grain of the streaker grain color of the
colorants in the extrudate without a capstock layer and/or in an
alternative embodiment of a capstock layer as well as the earlier
stated printing techniques. As shown in FIG. 13, the decorating
step combined with the embosser 30 provide supplemented grain color
337 along with low gloss texture 335 on the product 360. A printer
312 performs the decorating step wherein supplemented wood grain is
applied during vacuum embossing, or after vacuum embossing by
printer 311, or after the cooling tank 50, by printer 313. The
paint or inks from one or more paint applicators 310, 410 or
printers, alternatively 310, or 410, 311, 312 and/or 313 are
applied after each previously applied ink layer cools to
solidification, so that they provide overlapping and contrasting
color, or are applied prior to cooling and solidification of one or
more previously applied inks, so that the inks or colorants blend.
Alternatively, the extruded embossed product comprises a random or
irregular pattern of striations of recessed soft wood grain, and
striations of harder wood grain that appear to be raised relative
to the soft wood grain striations, as in FIG. 3B. Painted fence
boards are simulated further by having such striations that appear
with a coating of fresh paint applied by the painter 310, 410, as
described with reference to FIGS. 12 and 17. Accordingly, the
extruded embossed product of FIG. 3B comprises a painted board
having a random or irregular pattern of striations of recessed soft
wood grain, and striations of harder wood grain that appear to be
raised relative to the soft wood grain striations, when painted by
the painter 310, 410. Further, the painting operation covers
surface defects, for example, surface color defects and surface
abrasions.
[0084] As shown in FIG. 14, a fence board product 160 is provided
having a substantially hollow profile, with a hinge 169, one or
more sets of continuous lengthwise double ribs 164 combined with
corresponding continuous lengthwise single ribs 162. The fence
board product 160, alternatively comprises a single rib 162 with a
frictional interengagement and retention 161 with a set of two ribs
164, or further alternatively, a set of two ribs 164 having
complementary hook shaped latching surfaces 167, 168 interengaged
and latched to complementary latching surfaces on opposite sides of
a corresponding rib 162 therebetween. Alternatively, a series of
full length double ribs 164 and single ribs 162 are provided for
structural support through the hollow thickness of the fence board
160. A tongue and groove joint 166 is provided by extrusion at the
respective edges of the extrudate, which, preferably, includes a
mechanical locking or clasping arrangement, although this could
easily be a melt-bond if the temperature of the profile is high
enough upon joining, or heat is applied to the joint 166 during the
joining step of the joining device 177, such as by a heated sizer
of the calibration dies 40. As shown by the fence board product
160, a texture 135 and streaks of a grain color 137 are provided.
The streaks of a grain color 137 represent a different color,
contrast color, in the surface of the fence board product 160,
while the texture 135 represents low gloss peaks and valleys of
surface texture, a direct result of the vacuum embosser 30.
[0085] In FIG. 15, an extrusion, paint application and vacuum
forming chamber is provided in a fifth apparatus 500 for vacuum
forming polymeric material according to this invention. A
thermoplastic material with additives and colorants is extruded
from extruder 20 without a capstock layer, or alternatively with a
capstock layer 138 in FIG. 14A formed by extrusion of second
thermoplastic materials with colorants and additives in the
extruder 70 as an alternative embodiment of the invention. The
extruder 70 forms the capstock layer 138 on one major surface on
one side (capstock layer) on the extruded strip (substrate)
extrudate formed by the extruder 20 and the capstock extruder 70.
The extrudate is about 2-20 feet in continuous length. An
alternative embodiment of a decorator or paint applicator or
printer 410 is provided to increase or supplement the appearance of
wood grain color 137 by the application of additional colorants,
such as by the printer 410. The extrudate with its printed streaks
of a grain color or grain indicia 137 passes on to an embosser 425
in which vacuum or pressure forming equipment with one or more
forming chambers (two illustrated) with mold impression(s) of a low
gloss, wood-like texture 135 being impressed into the extrudate on
the exterior major surface of the product 160 in FIG. 14 or the
product 160' in FIG. 14A. The extrudate comprises the hollow
product 160, FIG. 14 or the product 160' in FIG. 14A, in an open
and flat configuration prior to being folded along the hinge 169 to
form a hollow configuration. The flat configuration is supported
against collapse thereof while the embosser 425 embosses the
exterior major surface of the extrudate with the pattern of
embossed texture 135. The semi-finished component, about 2-20 feet
in continuous length, comprising the extrudate with the texture
137, is then passed on or conveyed on rails 414 and 416 on to a
forming station 420 having, for example, the folding die 175 in
FIG. 4 and the joining device 177 in FIG. 4, in which an embodiment
of the embossed extrudate product is further formed and joined by
gluing, melt bonding, welding, or via mechanical means, to form a
low gloss, textured and hollow thin wall product 160 in FIG. 14 or,
alternatively 160' in FIG. 14A. Ideally, both lateral sides of the
embossed extrudate are unitary with each other along the hinge 169
and are folded and closed by joint 166, for example, such that the
texture 135 and streaks of a grain color or grain indicia 137 are
impressed into the product, e.g., four sides, for example.
Example A
[0086] A fence board trial was conducted using new embossing belts
on a vacuum forming machine with belt cooling fans. The following
compositions were employed:
[0087] substrate: PVC with additives such as stabilizers,
lubricants, impact modifiers, calcium carbonate and titanium
dioxide for UV protection.
[0088] capstock layer: ASA with additives such as stabilizers,
lubricants, impact modifiers, calcium carbonate and up to 10 parts
of titanium dioxide for UV protection.
[0089] This product was made in a co-extrusion process in which
substrate material PVC was extruded through a die by a first
extruder, and capstock layer ASA material was extruded into the
same die from another direction by a second extruder using the
following settings:
Extruder Conditions for Example A
TABLE-US-00001 [0090] Extruder Barrel Main-Extrusion Core or
Co-extrusion (ASA) Zones (BZ1-BZ4) Base Material Temperature
Temperature BZ1 (Throat) 370 330.degree. F. BZ2 360 330.degree. F.
BZ3 320 340.degree. F. BZ4 310 340.degree. F. Screw Oil Heater 310
290.degree. F. Temperature Die Temps 350 350.degree. F. Screw Motor
RPM 700 800 Hopper Feed Motor 150 80 RPM Belt Vacuum Inches -14''
Hg Dry Sizer (D.S.) -5'' Vacuum Ballast Tank -5'' Vacuum
[0091] Both the substrate and capstock layer materials merged in
the extrusion die and exited the die orifice (exit) as a single
hollow shape thin wall product made of two materials with each of
them having different compositions.
[0092] The following color settings, sequences and measurements
were made:
Color Settings for Example A
TABLE-US-00002 [0093] White Base Feed Pounds/Hour (lb/hr) 85 Color
Feed (lb/hr) n/a Brown Streaker Base Feed (lb/hr) 85 Color Feed
(lb/hr) 650 Clay Base Feed (lb/hr) 85 Color Feed (lb/hr) 400 Timber
Streaker Base Feed (lb/hr) 85 Color Feed (lb/hr) 650
[0094] The trial sequence was:
[0095] a. started with white pellets;
[0096] b. added Brown Streaker pellets 54120-A4 from Americhem
(still using PVC base);
[0097] c. changed to ASA/Clay pellets; and
[0098] d. added Timber Streaker pellets 9062-A3 from Americhem
(Centrex based color concentrate).
[0099] The melt temperature for PVC was 390.degree. F.; for ASA it
was 405.degree. F. The profile strung up very easily once again
with little or no difficulty attaining vacuum.
[0100] Auxiliary fans were used on both top and bottom belts for
cooling. The belt temperature was approximately 205-210.degree. F.
A belt temperature below 200.degree. F. will dramatically prolong
the belt life. All dimensions were achieved with puller and belt
speed adjustments. Currently, there is only one color feeder per
extruder. Streaked color will typically require two feeders.
[0101] The hollow shape thin wall profile exited the die in a soft
state with a high temperature and low rigidity. It then entered a
system made of one, two, or more flexible rotating belts being
strategically placed on the side(s) of the product where surface
texture is required. In order for the texture transfer process to
take place, the product had to be in a soft state. Vacuum was
employed to draw the product toward the textured surface of the
belt. For the vacuum force to take action, the vacuum chamber must
be sealed. Due to its soft state, the extruded profile by itself
can not support its own weight and the weight of sagging flexible
belt. As such, the vacuum chamber is not sealed and texture
transfer does not take place.
[0102] A floating mandrel(s) made of PTFE (or any other rigid
material with a low friction surface) was employed to increase the
rigidity of the system and close the seals between vacuum chamber,
rotating flexible belts, and constantly moving forward soft
extruded product. This floating mandrel(s) was attached by flexible
means to the stationary metal mandrel(s) of the extrusion die.
During the extrusion process, the floating mandrel located itself
in such a position in respect to the vacuum chamber, that it sealed
the extruded hollow shape thin wall product floating over the
mandrel(s), which helped to seal in the entire belt system. This
enabled the applied vacuum to pull the extruded product against the
textured belt surface so that texture transfer took place.
[0103] After exiting the rotating flexible belts, the extruded
product with a desired texture entered a vacuum calibration die
with a cooling tank following the calibration process. In the final
step of this process, the extruded product was cut to a desired
length.
[0104] The final product had improved texture, definition and lower
uniform gloss, when compared to a fence board of the same
composition, but without texture.
[0105] These were deemed to be very positive results. All of the
colors and material combinations produced very good looking
samples. The Brown Streaker was not used in conjunction with any
base colors, so it was just streaks on a light background color.
Timber Streaker didn't provide much of a streaking effect because
it melted so quickly in the ASA. Mandrels are attached to the die
by wire and stainless steel fasteners, such as, eyebolt, 304 SS,
3/16''-24, 2'' shank, 1'' thread. McMaster Carr p/n 9489T81.
[0106] The resulting board had a textured pattern with a gloss
reading of 27 on a 60.degree. glossmeter, whereas a smooth PVC
board made of the same materials had a gloss reading of 33 on a
60.degree. glossmeter. The gloss was measured with Glossmeter Model
500-60.degree., manufactured by Erichsen Testing Equipment.
Example B
[0107] A white fence board was produced by co-extrusion using a
parallel screw extruder 125 mm. screw diameter to extrude PVC
substrate, and a conical twin screw extruder 62 mm. screw diameter
to extrude PVC capstock.
[0108] substrate: PVC pellets with additives such as stabilizers,
lubricants, impact modifiers, calcium carbonate and titanium
dioxide for UV protection
[0109] capstock layer: PVC pellets with additives such as
stabilizers, lubricants, impact modifiers, calcium carbonate and up
to 10 parts of titanium dioxide for UV protection. PVC capstock is
used for light color products. (In our situation, PVC capstock is
used to produce white boards or light color boards).
[0110] The melted PVC substrate and melted PVC capstock merged in
the extrusion die and exited the die orifice (exit) as a single
hollow shape thin wall product made of two PVC based materials with
each of them having different compositions. The melt temperature
for PVC was 390 deg F. The hollow shape thin wall product after
exiting the die has smooth (flat) external surface.
[0111] The product was made with extruders settings as in the below
table:
TABLE-US-00003 Main-Extrusion Core or Co-extrusion (PVC) Extruder
Barrel Base Material Temperature Temperature Zones (BZ1-BZ4)
(.degree. F.) (.degree. F.) BZ1 (Throat) 370 350 BZ2 360 340 BZ3
320 320 BZ4 310 310 Screw Oil Heater 310 300 Temperature (.degree.
F.) Die Temps (.degree. F.) 350 350 Screw Motor RPM 700 800 Hopper
Feed Motor 150 80 RPM
[0112] After exiting die the hot and flexible hollow shape thin
wall product with smooth (flat) outside surface was pulled over
floating low friction rigid mandrels attached by flexible means to
pins in the die and suspended between silicone belts of the
equipment having a textured surface.
[0113] The settings of the vacuum belt velocity were set to equal
the exiting extrusion velocity of the thin wall hollow shaped
product of 12 feet per minute, as in the below table:
TABLE-US-00004 Belt Speed 34.0 Hz rheostat setting Belt Vacuum -14
inches Hg
[0114] After exiting the rotating flexible belts, the extruded
product with a desired texture entered a vacuum calibration die
with a cooling tank following the calibration process. The set up
of the calibration die and ballast vacuum tank was as in the below
table:
TABLE-US-00005 Dry Sizer Vacuum -5 inches Hg. Ballast Tank Vacuum
-5 inches Hg.
[0115] In the final step of this process, the extruded product was
cut to a desired length.
Example C
[0116] A fence board was produced by co-extrusion similarly as in
Example B, except for Example C comprising ASA capstock material
substituted for the PVC capstock material of Example B.
capstock layer: ASA pellets (with additives such as stabilizers,
lubricants, impact modifiers and titanium dioxide for UV
protection. ASA capstock is used for dark color products, for
example, dark brown and clay color boards.
[0117] Color concentrate pellets were added to both materials at
the same point as the material using separate single-screw color
feeders with settings as in the below table:
TABLE-US-00006 Clay Base Feed PVC (substrate) - Color concentrate -
1 lb/hr. 400 lb/hr. Capstock ASA feed - 100 lb/hr. Color
concentrate - 4 lb/hr. Brown Base Feed (substrate) - Color
concentrate - 1 lb/hr. 400 lb/hr. Capstock ASA feed - 100 lb/hr.
Color concentrate - 4 lb/hr.
Capstock extrusion rate is 100 lb/h. Color concentrate was fed to
the capstock material at a rate of 4 lb/hr. Substrate extrusion
rate was 400 lb/hr. with the color concentrate added.
[0118] PVC substrate with colorant and ASA capstock with colorant
merged in the extrusion die and exited the die orifice (exit) as a
single hollow shape thin wall product made of two materials: PVC
substrate and ASA capstock. The melt temperature for PVC was 390
deg F. and for the ASA capstock was 405 deg F. The hollow shape
thin wall product after exiting the die has smooth (flat) outside
surface. The product was produced with extruders settings as in the
below table:
TABLE-US-00007 Main-Extrusion Core or Co-extrusion (ASA) Barrel
Base Material Temperature Temperature Zones (B1-B4) (.degree. F.)
(.degree. F.) BZ1 (Throat) 370 330 BZ2 360 330 BZ3 320 340 BZ4 310
340 Screw Oil Heater 310 290 Die Temps 350 350 Motor RPM 700 800
Feed 150 80
[0119] After exiting die the hot and flexible hollow shape thin
wall product with smooth (flat) outside surface was pulled over
floating low friction mandrels attached by flexible means to pins
in the die and suspended between silicone belts of the equipment
changed from flat (smooth) external surface for impression in the
product to a textured surface.
Example D
[0120] According to Example D, a fence board was produced similarly
as Example C and with streaker pellets added to the capstock layer
of Example D.
substrate: PVC with additives such as stabilizers, lubricants,
impact modifiers, calcium carbonate and titanium dioxide for UV
protection capstock layer: ASA pellets (with additives such as
stabilizers, lubricants, impact modifiers and titanium dioxide for
UV protection. ASA capstock is used for dark color products, for
example, dark brown and clay color boards. Streaker pellets
#58437-87 from Americhem Inc., Cuyahoga Falls, Ohio 44221, added at
a rate of 2 lb/hr (corresponding to a feeder setting at 200).
[0121] Color concentrate pellets were added to both materials at
the same point as the material using separate single-screw color
feeders with settings as in the below table:
TABLE-US-00008 Clay Base Feed PVC (substrate) - Color concentrate -
1 lb/hr. 400 lb/hr. Capstock ASA feed - 100 lb/hr. Color
concentrate - 4 lb/hr. Streaker - 2 lb/hr. Brown Base Feed
(substrate) - Color concentrate - 1 lb/hr. 400 lb/hr. Capstock ASA
feed - 100 lb/hr. Color concentrate - 4 lb/hr. Streaker - 2
lb/hr.
[0122] From PVC substrate with colorant and ASA capstock with
colorant and streaker merged in the extrusion die and exited the
die orifice (exit) as a single hollow shape of thin walls made of
two materials: PVC substrate with colorant, and ASA capstock with
colorant and streaker. The melt temperature for PVC was 390 deg F.
and for the ASA capstock was 405 deg F. The hollow shape thin wall
product after exiting the die has smooth (flat) outside
surface.
[0123] The product was produced with the same, extruder(s)
settings, belt settings and vacuum calibration die settings as for
Example C.
[0124] The patents and applications referred to are hereby
incorporated by reference herein.
[0125] From the foregoing description, an invention provides
exterior building materials that include hollow, closed, thin wall
profiles comprising a polymeric composition including additives and
colorants. The exterior facing surface of the profile includes a
low gloss, textured pattern disposed continuously along the
exterior facing surface portion for about 2-20 feet. The present
invention provides texture, pattern and low gloss similar to real
wood products. The combination of extrusion processing with
continuous vacuum embossing processes is capable of enhancing
product appearance by applying a low gloss pattern in any
direction, including the cross-extrusion direction, to thin wall
product surfaces so as to emulate wood texture. In particular,
hollow profile extrusion in combination with continuous vacuum
embossing processes can be used to produce useful building
materials emulating a natural texture. Furthermore, the combination
of thermoplastic materials with colorants and/or a combination of
extrusion processes with in-line decorating processes will add
grain as a final parameter of natural wood fence boards, decking
and other exterior building products.
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