U.S. patent application number 11/247620 was filed with the patent office on 2007-04-26 for building material having a fluorocarbon based capstock layer and process of manufacturing same with less dimensional distortion.
Invention is credited to Jong P. Jeng.
Application Number | 20070092701 11/247620 |
Document ID | / |
Family ID | 37985718 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070092701 |
Kind Code |
A1 |
Jeng; Jong P. |
April 26, 2007 |
Building material having a fluorocarbon based capstock layer and
process of manufacturing same with less dimensional distortion
Abstract
The present invention provides building materials and methods
for the manufacturer which includes an extrudable thermoplastic or
thermosetting substrate having a fluorocarbon-based capstock layer
applied to the substrate. The fluorocarbon-based capstock layer can
further include one or more top coats for providing a variegated,
colored or textured pattern. The capstock layer, with or without
the top coats, preferably has a thickness less than 4 mil and
contains a UV-resistant PVDF resin.
Inventors: |
Jeng; Jong P.; (Maple Glen,
PA) |
Correspondence
Address: |
DUANE MORRIS, LLP;IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103-4196
US
|
Family ID: |
37985718 |
Appl. No.: |
11/247620 |
Filed: |
October 11, 2005 |
Current U.S.
Class: |
428/195.1 |
Current CPC
Class: |
B29C 2793/0027 20130101;
B29L 2031/722 20130101; B29C 48/911 20190201; E06B 3/22 20130101;
B29K 2027/16 20130101; B29L 2031/104 20130101; B29C 48/07 20190201;
B29C 48/001 20190201; B41M 3/06 20130101; B29L 2031/10 20130101;
B29L 2031/108 20130101; E04F 13/185 20130101; E06B 3/30 20130101;
Y10T 428/24802 20150115; B05D 2201/00 20130101; B05D 2256/00
20130101; B29C 59/043 20130101; B29K 2027/06 20130101; E04C 3/28
20130101; B29C 48/12 20190201; B29C 48/09 20190201; E04C 2003/023
20130101; B29C 48/21 20190201; B41M 3/00 20130101; B05D 2506/10
20130101 |
Class at
Publication: |
428/195.1 |
International
Class: |
B41M 5/00 20060101
B41M005/00; G03G 7/00 20060101 G03G007/00 |
Claims
1. An exterior building material comprising: a) a substrate
containing PVC, polyethylene, polypropylene, polystyrene or
mixtures thereof; and b) a capstock layer applied directly to said
substrate, said capstock layer comprising a fluorocarbon resinous
composition.
2. The building material of claim 1 wherein said building material
forms a portion of a roofing slate, tile or shake, a siding panel,
a window profile, a decking member, a fencing member, or a trim
board.
3. The building material of claim 1 comprising a variegated colored
pattern layer disposed over said capstock layer.
4. The building material of claim 1 wherein said capstock layer
comprises UV blocking properties.
5. The building material of claim 3 wherein said variegated colored
layer comprises at least one top coating layer comprising a
fluorocarbon resin, said capstock and top coating layer providing a
variegated appearance indicative of a wood grain.
6. The building material of claim 1 wherein said capstock layer
comprises long term weathering performance, mildew resistance, dirt
repellency, and good adherence to said substrate.
7. The building material of claim 1 wherein said capstock layer
comprises a formulated resin system comprising a copolymer of PVDF
and Hexa Fluoro PVDF.
8. The building material of claim 1 wherein said capstock layer
comprises a thickness of less than 4 mil.
9. The building material of claim 1 wherein said capstock layer
comprises an opaque resinous formulation which is 100% resistant to
UV penetration.
10. A building material comprising a base substrate comprising PVC,
a UV resistant capstock layer comprising PVDF or ASA, and a first
top coat layer comprising PVDF resin, said capstock and top coating
layer providing a variegated appearance indicative of a wood grain,
without bowing said substrate in any significant way.
11. The building material of claim 10 further comprising a second
top coat layer disposed over said first top coat layer to provide a
variegated appearance, said second top coat layer having a
different appearance from said first top coat.
12. The building material of claim 11 wherein said capstock layer
comprises an opaque composition which is 100% resistant to UV
penetration.
13. The building material of claim 12 wherein said capstock layer,
said first top coat layer and said second top coat layer comprise a
total thickness of about 4 mil or less.
14. The building material of claim 10 wherein said capstock layer
self-adheres without a primer to said PVC-containing base
substrate.
15. A method of making an exterior building product comprising: a)
extruding a thermoplastic polymeric material comprising PVC,
polyethylene, polypropylene, polystyrene, or mixtures thereof to
form a base extrudate; b) coating said base extrudate in line,
while still hot, with a fluorocarbon-based or acrylic-based
capstock layer; and c) drying said capstock layer to form a
UV-resistant protective layer on said base extrudate.
16. The method of claim 15 wherein said coating step (b) comprises
spraying, printing or painting said fluorocarbon-based capstock
layer without a primer layer.
17. The method of claim 15 wherein said coating step (b) comprises
employing one or more of a paint spraying step, an ink jet printing
step, or a gravure roll printing step.
18. The method of claim 15 wherein said drying step (c) relies, at
least in part, upon heat generated by said extruding step.
19. The method of claim 15 wherein said capstock layer comprises a
thickness of less than 4 mil.
20. A method of making an exterior building product including
siding, window profiles, decking, fencing, trim boards, or a
combination thereof, comprising: a) extruding a thermoplastic
polymeric material comprising PVC to form a base extrudate having
an elevated temperature; b) coating said base extrudate in line,
with a UV-resistant PVDF-based liquid capstock layer while said
extrudate is still hot, and permitting said liquid capstock layer
to dry, whereby said dried capstock and top coat layers form a
variegated pattern having a thickness of about 4 mil or less,
without warping or bowing said exterior building product. c)
applying at least one top coat to said capstock layer to provide a
variegated appearance, and permitting said top coat to dry.
21. A roofing slate, tile or shake made from the process of claim
15.
22. A siding panel made from the process of claim 15.
23. A window profile made from the process of claim 15.
24. A decking member made from the process of claim 15.
25. A fencing member made from the process of claim 15.
26. A trim board made from the process of claim 15.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to U.S. Ser. No.
10/389,400 filed Mar. 14, 2003, now U.S. Pat. No. 6,752,941
(D0932-00229), which are hereby incorporated by reference in its
entirety. The Examiner is directed to inspect the complete files of
this earlier application for any material information concerning
the instant claims.
FIELD OF THE INVENTION
[0002] The present invention relates to building materials having a
capstock which may contain durable imagery to simulate actual
surface textures, colors and appearances, and more particularly,
siding, decking, window and fencing components having a wood
grain.
BACKGROUND OF THE INVENTION
[0003] Vinyl siding was introduced in the early 1960's, but did not
gain much attention until the 1970's. During the 1980's and 1990's,
its use increased dramatically. Siding is the second largest market
for polyvinyl chloride ("PVC") resin, after pipe manufacturing,
with approximately one billion pounds of resin used for this
purpose in 1992. Vinyl siding is manufactured by a co-extrusion
process in which two layers of PVC are generated in a continuous
manner. The top layer called a capstock layer, comprises about
one-quarter to one-third of the siding thickness and includes about
10% titanium dioxide, which is an opaque filler that provides some
measure of UV protection for the lower layer, typically called the
substrate. The substrate typically includes about 15% calcium
carbonate, which balances the weight of the titanium dioxide to
keep both extrusion streams equally fluid during manufacturing. A
small quantity of a stabilizer such as tin mercaptan or butadiene
is added as a stabilizer to chemically tie up any hydrochloric acid
that is released into the PVC material as the siding ages.
Lubricants may also be added to aid in the extrusion manufacturing
process.
[0004] Vinyl siding is often considered a cheap substitute for
wood, and is favored in some markets because of its lower
maintenance requirement, it generally doesn't need to be painted or
stained like real wood. Nevertheless, due to sun exposure, vinyl
siding colors can dull and the surface of siding can become
chalky.
[0005] Accordingly, artisans have continued to develop improved
resin formulations for capstock layers to minimize the degradation
of siding, decking, window, and fencing products made from PVC due
to exposure of weather conditions including moisture and sunlight.
For example, Solarkote.RTM. PB acrylic capstock resin from Atoglas
of Philadelphia, Pennsylvania has been commercialized as a capstock
resin for imparting long lasting weatherability and enhancing the
color and appearance of PVC substrates. When blended with PVC resin
and co-extruded over PVC substrates as a capstock, Atoglas claims
its Solarkote.RTM. PB acrylic resin upgrades PVC properties for
exterior building products. The manufacturer also claims that
Solarkote.RTM. PB/PVC blends impart weathering performance in
medium dark colors where chalking can be an issue. Additionally,
Atoglas' literature states that this coating exhibits improved
color hold in whites--even at higher elevations in locations such
as Arizona and Colorado. Solarkote.RTM. Acrylic capstock resin is
advertised as screening out UV radiation in layers as thin as 6 mil
(0.006 in). It is further suggested that this resin is suited for
co-extruded applications for use in watercraft, recreational
vehicles, lawn and garden products, building construction,
automotive accessories, outdoor enclosures, tubs, spas and pool
accessories.
[0006] Atoglas advertises that its Solarkote.RTM. capstock can be
provided in a multi-layered form to often eliminate the need for
painting. This three-layer co-extruded structure includes a
polycarbonate, ABS, HIPS, acrylic-styrene-acrylonitrile,
polycarbonate, PETG, or vinyl, plus two acrylic layers. Autoglas
also advertises that by extruding the pigment in the center acrylic
layer, the color effect has more depth and is better protected from
scratches and weathering problems. The top layer is suggested as
including a UV package that protects the pigment in the subsequent
layer and the Solarkote.RTM. acrylic resins permit the designer to
choose between matte, gloss and frosted effects. See trade
literature articles entitled "Acrylic Resin Improves PVC Substrate
Appearance" Thomas Net Industrial Newsroom Aug. 16, 2002 and "New
Solarkote.RTM. PV Acrylic Capstock Resin from Autoglas Improves
Weatherability and Appearance of PVC Substrates" Thomas Net
Industrial Newsroom Aug. 7, 2002, (www.news.thomasnet.com) and
trade literature entitled "Capstocks, Films Vie to Protect Outdoor
Protects, Modem Plastics Worldwide Copyright 2003,
(www.modplas.com/inc/m article).
[0007] In addition to color retention, manufacturers have also been
focusing on producing vinyl building products with simulated
wood-grain or other multi-colored appearances. Various methods of
manufacturing such plastic articles have been used, but very few
have succeeded in achieving a realistic wood-grain appearance in
which the wood grain is strongly accented against a background
layer. Typical processes involve blended colors including streaked,
semi-transparent stained wood appearances often achieved through a
multi-viscosity fusion process. This multi-viscosity fusion process
uses multiple colorants of different viscosity, or thicknesses.
Each color flows and mixes differently in the extruder. The first,
usually a lighter color, melts easily and quickly and, thus, forms
the background color for the siding. The second, usually a darker
color, melts later in the extrusion process and streaks because it
does not disperse completely. The blended effect is actually the
darker color sitting on top of the lighter base color, creating a
semi-transparent stained wood appearance. See, for example, U.S.
Pat. No. 4,048,101 to Nakamachi, assigned to Daicel Ltd., and U.S.
Pat. No. 5,387,381 to Saloom, assigned to Alcan Aluminum
Corporation, and trade literature entitled Wolverine Master
Craftsmen Education and Development Program.COPYRGT. 2002
Wolverine, page 12 (www.siding.com).
[0008] Applicants have also experimented with using transparent
pigment blends having different vicat softening temperatures based
on poly-alpha-methylstyrene or other polymers, such as acrylic,
acrylic-styrene acrylonitrile (ASA),
acrylonitrile-ethylene-propylene-styrene (AES) or other
transparent, opaque and/or translucent, weatherable polymers, or
combinations of PVC and one or more of the above-noted polymers.
See U.S. Pat. No. 6,752,941.
[0009] Through its experience in manufacturing PVC siding with ASA
capstock, CertainTeed Corporation has observed that existing ASA
capstock material has a fairly narrow processing window during
extrusion with unfortunate consequences if the processing window is
missed. If the processing temperature is too high during the
manufacturing of such products, the melt viscosity of the capstock
will become sticky; if the temperature is too low, the melt flow
will center around the die.
[0010] There is also a noticeable difference in the coefficient of
linear thermal expansion between ASA and PVC. This can lead to a
difference in contraction rates during cooling between the
predominantly ASA capstock and the predominantly PVC substrate,
which can lead to undesirable bowing or dimensional distortion of
the building material. It has also been noticed that for many
variegated products using streaker pigment in acrylic based
capstocks, it is inherently difficult to control the melt rheology
in the ASA matrix for consistent streak wood grain patterns.
[0011] Notwithstanding the thermal contraction rate problem between
ASA and PVD in siding products, others have developed techniques of
providing wood grains by printing. See U.S. Pat. No. 6,823,794 to
Bosler et al., and assigned to Bosler Designs, Inc. The '794 patent
describes a method for printing an extruded sheet which includes
the steps of extruding a sheet having an elevated temperature in
the range of about 250.degree. F. to about 450.degree. F. and
applying a heat curable ink or evaporable ink over the extruded
sheet having the elevated temperature whereby the ink is cured
immediately upon contact. The machinery selected by Bosler et al.
can include multiple print rollers for printing in order to
formulate a combination of colors. A plastisol ink which cures at a
temperature of about 140.degree. F. to about 200.degree. F. along
with evaporable inks and any conventional ink which cures upon
contact with a material having an elevated temperature is
suggested.
[0012] While printing variegated colors and textures such as wood
grains could alleviate the above-mentioned consistency problem
associated with providing streaked stained wood appearances through
a multi-viscosity fusion process, there is no suggestion in Bosler
et al. for overcoming the distortion problems caused by differences
in the coefficient of liner thermal expansion. In fact, the '794
patent mentions that its extrudable plastic substrate material can
include ASA, and there is no recognition in Bosler et al. regarding
the contraction rate problem or its solution.
[0013] Accordingly, there is a present need for an improved
capstock material which provides the weatherability of traditional
co-extruded coatings and which enables detailed variegated
patterns, without distortion or dimensional tolerance problems, or
melt rheology complications.
SUMMARY OF THE INVENTION
[0014] This invention provides, in a first embodiment, an exterior
building material which includes a substrate containing a
thermoplastic, such as PVC, polyethylene, polypropylene,
polystyrene or mixtures thereof and a capstock layer applied
directly to the substrate, said capstock layer comprising a
fluorocarbon resinous composition.
[0015] The present invention can be applied to all types of
PVC-based products, for example, siding, windows, decking, fencing,
trim boards, etc., which generally require a capstock layer to
protect them from long term weathering. The inherent problems
associated with using existing capstock materials such as ASA or
other acrylic resinous compositions, including narrow processing
windows and different coefficients of linear thermal expansion
values compared to typical thermoplastic substrates, can be
overcome by this invention.
[0016] The preferred embodiment of this invention employs a thin,
coated, painted or printed capstock layer of about 4 mil or less,
preferably 1 mil or less, of a fluorocarbon or acrylic-based
resinous composition, for example, containing polyvinylidene
fluoride ("PVDF") resin. The capstock can, alone or with further
coatings, provide a stone, wood or various other appearance
characteristics found in other naturally occurring materials. The
particular stone "effects" include the appearance characteristics
found in synthetic, man-made, metamorphic, sedimentary and/or
igneous rocks or natural formations. The particular wood effects
include those of grain, color, texture and patterns of synthetic
and/or naturally occurring wood and wood-like products, or other
organic materials, such as bamboo, straw or cork, for example.
[0017] The use of special formations and thin inks, paints or
coatings can create consistent special effects, such as variegated
wood grains. This invention preferably employs direct printing
and/or coating operations for providing both the capstock and,
optionally, further layers, which are performed independently of
the extrusion process, so as to provide extremely thin coatings to
substantially eliminate bowing and dimensional distortion of panel
siding, window lineals and other building products. The
minimization of bowing and dimensional distortion is achieved by
thinner cross-sections, more compatible resins from a coefficient
of lineal thermal expansion point of view, the elimination of
co-extruded ASA capstock processes, or a combination thereof.
[0018] In a most preferred embodiment of this invention, a PVDF
polymer such as a water-based emulsion ink or paint containing a
copolymer of PVDF and Hexa Fluoro PVDF that is polymerized in the
presence of an acrylic component is used for the capstock layer.
Such coatings can present an interpenetrating network that is
highly compatible or especially adherent to PVC substrates. A
primer coating is not necessary.
[0019] In other preferred embodiments of the present invention, a
method of making an exterior product is provided. This method
includes extruding a thermoplastic polymer material comprising PVC
to form a base extrudate, coating the base extrudate in-line, while
still hot, with a capstock layer comprising a fluorocarbon based
resinous composition, and drying the capstock layer to form a
UV-resistant protective layer on said base extrudate.
[0020] In this and other processes of this invention mono-extrusion
techniques are preferred. The spraying, painting, ink jet printing,
or gravure roll printing (hereinafter "coating operation") can be
located between the extrusion die and the sizer or cooling tank.
The extruded material can be printed or coated at a high speed
while its surface temperature is high and the material is still
pliable. Preferentially, the coating operation can be integrated
in-line rather than less desirably as a secondary post-treatment
process. The capstock of this invention can be further coated with
one, two, three or more additional layers. For example, the
capstock layer can represent a background layer, and the top layers
can include a pair of variegated printing layers. The capstock
layer and each additional layer can be transparent, translucent or
opaque with dyes, or colored or pigment inks, to provide a final
effect or variegated appearance. The capstock layer is, preferably,
an opaque composition which may contain a metal oxide, such as
TiO.sub.2 for UV resistance.
[0021] In one preferred embodiment of this invention, the coating
or printed layer includes 100% opaque Kynarg liquid PVDF resin
applied onto the extruded hot PVC substrate to provide an aesthetic
durable and UV light resistant capstock. The preferred Kynar.RTM.
resin is a formulated resin system comprising a copolymer of PVDF
and Hexa Fluoro PVDF that is polymerized in the presence of an
acrylic component. Kynar.RTM. PVDF is provided by Arkema, Corp.
(www.products.arkemagroup.com).
[0022] The present invention can also be useful in connection with
roofing materials, such as synthetic slates, tiles or shakes, or in
multi-shake roofing panel products. For example, the capstock layer
of this invention can be applied directly to a roofing substrate so
as to present a printed or otherwise aesthetic appearance to
synthetic slates, tiles or shakes, to make them more realistic in
appearance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The disclosed invention will be described with reference to
the accompanying drawings, in which:
[0024] FIG. 1: is a diagrammatic side elevation of a preferred
process line for manufacturing the building materials of this
invention;
[0025] FIG. 2: is a front partial perspective view of a window
lineal produced in accordance with this invention;
[0026] FIG. 3: is a front partial perspective view of a siding
member produced in accordance with this invention;
[0027] FIG. 4: is an enlarged view of a portion of the window
lineal of FIG. 2, showing a preferred number of layers; and
[0028] FIG. 5: is a bar chart showing UV weatherability for various
coatings shown in the Example.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The present invention relates to creating patterns such as
variegated colors or wood grains on building materials, for
example, decking, fencing, railing, siding and window framing
applications, to name a few. This invention employs 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.
[0030] With reference to the FIGURES, and particularly FIG. 1
thereof, there is shown a manufacturing process 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 calcium carbonate, TiO.sub.2 and other
micro-ingredients can be added to create the processing compound.
This precise measuring of ingredients and uniform blending under
proper heat conditions can be important to the production of
uniform, high quality building products.
[0031] After blending, the compound is conveyed to the extrusion
line where it is carefully metered so a consistent amount enters
the extruder 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, such as
PVC, PVC and wood pulp, PVC and copolymers, and/or other
thermoplastics such as polystyrene, polyethylene, polypropylene, or
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 PVC
and the micro-ingredients in the compound.
[0032] Most vinyl siding is 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 PVC 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 siding
product.
[0033] In many past examples, co-extrusion has been used to join
two flows of molten PVC compound from two extruders in a single die
to produce a single sheet made of two layers of material, such as
substrate and "capstock." As used herein, the term "capstock"
refers to a thin protective layer added to some vinyl building
products to improve weatherability and color retention. Typically,
the capstock material is made of an acrylic-containing resin, such
as AES or ASA. Existing ASA capstock co-extrusion requires a fairly
narrow processing window due to the difference in coefficient of
linear thermal expansion between ASA and PVC. Missing this window
often leads to unacceptable dimensional distortion or bowing of the
panel, lineal or board, for example. Additionally, the variegated
streaker pigment, used to provide a variegated or wood grain
product is inherently difficult to control in an ASA matrix for
consistent streak wood grain patterns.
[0034] Accordingly, this invention preferably employs one or more
spraying, painting, and/or printing steps ("coating step") which
follows the extrusion or co-extrusion step for providing both a
capstock layer 101 and one or more top coat layers 102, 103 to
provide a variegated textured or colored pattern to the building
material. This variegated pattern can include a wood grain and can
be provided in one or more coating layers. The coating step can
include spraying, inkjet printing or gravure roll coating, for
example. A gravure roll coater 20 is located between the embossing
rollers 12 and the cooling tank 30 in the preferred manufacturing
schematic of FIG. 1. Further details of the printing equipment
useful for this purpose are provided in U.S. Pat. No. 6,823,794 to
Bosler et al, which is hereby incorporated by reference.
[0035] As the extrudate exits the extruder 10, the vinyl sheet is
still very hot, nearly molten. Between the extruder and the gravure
roll coater 20 is typically located a textured roll and rubber roll
12 (collectively) for embossing. Depending on the rollers, and if
embossing is required, siding and decking products and accessories
are typically embossed in either rough cedar, wood grain, smooth
brushed or a smooth finish that looks like sanded, sealed and
painted wood. The coating step, shown in the exemplary embodiment
as employing a gravure roll coater 20 ("print roll"), can be
located before or after the embossing step, or before or after the
sizer, for example.
[0036] Some building products are also treated with a post-forming
step, which includes equipment, such as sizers and formers, which
provide greater consistency in thickness and profile. Post-formed
locking devices in siding, for example, have tighter tolerances and
more intricate interlocking structures, which can result in higher
wind load ratings. Post-forming operations can further include
pre-sizers and vacuum sizers immediately prior to the cooling tank
30 to create distinctive profiles and a wide range of sizes for
vinyl products. In a vacuum sizing calibrator (not shown), the
sizing is given a crisp finish profile.
[0037] The cooling tank 30 can be located after any post-forming
operation. Once the hot sheet including the painted or printed
layer 16 over the PVC substrate 15 is introduced into the cooling
tank 30, the panel temperature quickly drops and the final shape
sets. The preferred painted or printed capstock layer can be dry
before, during or after being cooled in the cooling tank 30.
Preferably the capstock coating step occurs prior to water cooling,
so that the substrate's heat of extrusion can be used to dry the
capstock coating. In one preferred embodiment, one or more computer
controlled ink-jet printers can be used for depositing one or more
print layers in rapid succession, such as a 100% opaque capstock
layer followed by two or three printed variegated layers, prior to
water cooling.
[0038] After passing through the cooling tank 30, the PVC substrate
15 and painted or printed layer 16 is punched at precise intervals
for nail holes. This can be accomplished with a nail punch 40.
Finally, the siding is cut to length at cut off 50, inspected and
packaged.
[0039] As shown in FIGS. 2-4, a window lineal 55 and siding 60,
made pursuant to this invention, are provided. The window lineal 55
and siding 60 include a preferred simulated wood-grain or
multi-colored appearance. This variegated effect or appearance can
be produced by employing transparent, translucent, or opaque
polymer matrices and color particles, such as pigments and dyes,
and reflective and semi-reflective materials, such as mica, and
textured materials, such as wood pulp, wood or paper pulp, for
example. See U.S. Pat. No. 6,752,941 and U.S. patent application
Ser. No. 10/983,389 which are hereby incorporated by reference in
its entirety.
[0040] As shown in FIG. 4, the preferred coating or capstock layer
comprises a capstock layer 101, first top coat layer 102, and
second top coat layer 103, disposed over a thermoplastic or
thermosetting substrate 100. One or more of the capstock layer 101,
first top coat layer 102, and second top coat layer 103 can include
pigments or effects for creating a wood grain 104, or other pattern
or texture. The use of the preferred inks, pigments, coatings or
paints can create consistent variegated wood grains, textures and
colors. By direct printing or coating, for example, these effects
can be provided without distortion or bending of thin panels, long
decking planks, or intricate widow lineals. 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. Bowing can be minimized since hot co-extruded ASA
capstock can be avoided.
[0041] While various coatings can be employed in connection with
variegated surfaces of this invention, fluorocarbon resinous
compositions, including PTFE, PFA, ETFE, ECTFE, FEP, PVDF, PPS,
EFEP, TEFLOND, and other thermoplastic or thermosetting resins, are
desirable. These compositions can be 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.
[0042] The preferred method of this invention for making the
capstock layer 101 and the first and second top coat layers 102,
103 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. Kynar.RTM. PVDF
coatings are tough engineering thermoplastics that are resistant to
harsh thermal, chemical and ultraviolet environments. Kynar.RTM.
resins are readily melt-processed by standard methods of extrusion
and injection compression molding, and can be dissolved in polar
solvents such as organic esters and amines. The selective
solubility is an advantage in the preparation of corrosion
resistant coatings for long-life architectural finishes on building
materials.
[0043] Both rigid and flexible versions of Kynar PVDF resin are
available. While Kynar.RTM. resins are usually melt-processed by
extrusion, injection molding, compression molding and the like,
they can also be provided in functional powder coating systems,
resins for rotational molding and open and close cell foams.
Desirable versions of Kynarg resin include Kynar 500.RTM. resin for
architectural applications and Kynar Aquatec water based PVDF
coating. The Kynar 500.RTM. resin for architectural applications is
polyvinylene fluoride PVDF, used as a base resin in a liquid
coating formulation by paint manufacturers. When formulated into a
coating composition, which contains a minimum of 70 weight % of
Kynar 500.RTM. resin, the resulting coating exhibits color
retention, gloss retention, chalk resistance, corrosion resistance,
flexibility, and stain resistance. Plastisols, emulsions,
solvent-based and water-based resin systems are useful within the
context of this invention.
EXAMPLE
[0044] TABLE-US-00001 TABLE 1 Working example of Liquid Cap-Stock
Ingredient Supplier phr* Substrate Compositions PVC Resin
CertainTeed 100 Methyl tin Stabilizer Arkema 1.0 Lubricant 1, Ca
Stearate Baerlocher 1.4 Lubricant 2, PE Wax Honeywell 0.2.about.0.3
Lubricant 3, Paraffin Wax Honeywell 1.5 Impact Modifier, Acrylics
Rohm and Haas 4.0 Pigment, TiO2 Kronos, DuPont 0.8 Filler, CaCO3
Specialty Mineral 10.0 Capstock Selections 1.
Acrylonitrile-styrene-acrylate BASF 100 (ASA) based copolymer 2.
PVC Cap-Stock CertainTeed 100 *phr = parts per hundred in reference
to the PVC loading level
[0045] TABLE-US-00002 TABLE 2 PVC Cap-Stock Composition Ingredient
Supplier phr PVC Resin CertainTeed 100 Methyl tin stabilizer
Crompton(chemtura) 1.2 Lubricant 1, Ca Stearate Baerlocher 1.7
Lubricant 2, PE Wax Honeywell 0.2 Lubricant 3, Paraffin Wax
Honeywell 0.2 Processing aid, Acrylics Rohm and Haas 0.5 Impact
Modifier, Acrylics Rohm and Haas 4.0 Paint Selections 1.
Polyvinylidene Fluoride (PVDF) 2. Kynar based copolymer Kalcor
100
[0046] TABLE-US-00003 TABLE 3 Typical paint formulation wt. wet wt.
vol. Add in order: grams vol. solids solids Notes KYNAR AQUATEC
90.60 75.50 43.50 29.00 KYNAR AMF RC-10,147 latex Ammonia 29% 0.55
0.55 0.00 0.00 Neutralizing agent Gray grind 12473-6-1 33.85 14.05
27.35 7.32 Dipropylene glycol 4.35 4.65 0.00 0.00 Coalescing methyl
ether agent Acrysol RM-825:water 0.50 0.50 0.10 0.10 Thickener (1:4
dilution) (Rohm and Haas) DI water 4.75 4.75 0.00 0.00 TOTAL 134.6
100.0 70.95 36.42
[0047] TABLE-US-00004 TABLE 4 UV Opacity of Liquid Cap-Stock Test
Results Paint Formulation 1 Coating Thickness 3 mil 2 mil 1 mil Dry
Film Thickness, mils 0.60 0.40 0.24 wavelength, nm UV Transmission
(%) 312 -0.012 0.1404 340 -0.006 0.1553 364 -0.006 0.1889 400 0
0.2512 500 0.048 0.4229 Paint Formulation 2 Coating Thickness 3 mil
2 mil 1 mil Dry Film Thickness, mils 0.53 0.35 0.20 wavelength, nm
UV Transmission (%) 312 -0.011 -0.014 0.0934 340 -0.003 -0.006
0.0834 364 -0.018 -0.017 0.0735 400 -0.006 -0.003 0.1073 500 0.0006
0.0247 0.1824
[0048] The weatherability at 1000 hours of paint formulations 1 and
2 in TABLE 2 "Paint Selections", compared to a control having a
standard BASF ASA coating, is shown in FIG. 5, wherein Delta E
represents the total color difference or change, which is a single
number that expresses the magnitude of the difference between two
colors, e.g., before and after exposure to the elements.
[0049] Components can either be coated or printed in-line prior to
water cooling, post-formed from pre-coated polymeric building
materials or spray coated after fabrication in the final assembly,
Kynar Aquatec provides Kynar.RTM. resins in a convenient emulsion
form. Coatings formulated from these emulsions provide the combined
benefits of extreme weatherability in a VOC-compliant field, or an
ambient dry system. The coated, printed or painted layer 16 of this
invention can include blended colors, light colors or dark colors.
Darker colors, particularly black, blues, greens, browns and grays,
tend to absorb more UV light than lighter colors, and would quickly
chalk or fade if made in only PVC. The Kynar.RTM. based inks and
coatings of this invention ensure long term weatherability for
these dark colors.
[0050] From the foregoing, it can be realized that this invention
provides more dimensionally stable thermoplastic and thermosetting
building components having a variegated, colored and/or textured
appearance. By printing or coating the capstock layer of siding or
decking, for example, following the extrusion step, less material
can be employed which minimizes expenses. This process also
minimizes any differences in the coefficient of lineal thermal
expansion between the capstock and the underlying substrate. The
Kynar.RTM. inks or paints of this invention can be water-based
systems that can be applied directly without primer onto PVC
substrates at less than 400.degree. F., preferably about
250.degree. F.-340.degree. F. (120-170.degree. C.), a rapidly. The
application techniques can include painting, gravure roll printing,
spraying, or inkjet printing. The Kynar.RTM. resin system can serve
as both the capstock layer as well as a printing background
simultaneously, and optionally, can serve as one or more top
printing layers with colored Kynar.RTM. inks to give a final
variegated appearance.
* * * * *