U.S. patent application number 11/054258 was filed with the patent office on 2006-07-06 for foil or film laminated enhanced natural fiber/polymer composite.
Invention is credited to Paul Brestelli, Douglas G. Mancosh, James Przybylinski.
Application Number | 20060147693 11/054258 |
Document ID | / |
Family ID | 36640789 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060147693 |
Kind Code |
A1 |
Przybylinski; James ; et
al. |
July 6, 2006 |
Foil or film laminated enhanced natural fiber/polymer composite
Abstract
A natural fiber/polymer composite product that includes a core
(preferably with a textured surface) and a film or pigment surface
layer applied to that textured core surface. The core comprises at
least one natural fiber and at least one polymer intimately admixed
together to form a composite.
Inventors: |
Przybylinski; James;
(Corvallis, OR) ; Mancosh; Douglas G.; (Warwick,
RI) ; Brestelli; Paul; (Stanfield, NC) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Family ID: |
36640789 |
Appl. No.: |
11/054258 |
Filed: |
February 9, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60641308 |
Jan 4, 2005 |
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Current U.S.
Class: |
428/292.1 |
Current CPC
Class: |
B32B 2305/22 20130101;
B32B 27/304 20130101; B32B 2260/046 20130101; B32B 2419/04
20130101; B32B 2274/00 20130101; B32B 27/12 20130101; B32B 37/153
20130101; B32B 2307/71 20130101; B32B 27/302 20130101; B32B 2305/08
20130101; B32B 2262/067 20130101; B32B 2419/00 20130101; B32B 27/32
20130101; B32B 2310/14 20130101; B32B 2038/002 20130101; B32B
2260/021 20130101; B32B 38/0008 20130101; B32B 2307/712 20130101;
Y10T 428/249924 20150401; B32B 37/12 20130101 |
Class at
Publication: |
428/292.1 |
International
Class: |
D04H 13/00 20060101
D04H013/00 |
Claims
1. A natural fiber/polymer composite product comprising,: (a) a
core comprising at least one natural fiber and at least one polymer
intimately admixed together, said core comprising a mechanically or
chemically prepared surface; and (b) at least one layer on said
mechanically or chemically prepared core surface, said layer
comprising either: a) a film layer laminated onto said mechanically
or chemically prepared core surface; or b) a layer that has been
hot stamped from a foil onto said mechanically or chemically
prepared core surface.
2. A natural fiber/polymer composite product comprising, (a) a core
comprising at least one natural fiber and at least one polymer
intimately admixed together, and (b) at least one layer hot stamped
from a foil onto a surface of said core.
3. A natural fiber/polymer composite product comprising, (a) a core
comprising at least one natural fiber and at least one polymer
intimately admixed together; and (b) at least one layer laminated
onto a surface of said core.
4. A natural fiber/polymer composite product formed by, (a) first
extruding at least one natural fiber and at least one polymer to
form a composite core having a smooth surface; (b) providing a
mechanical or chemical preparation to said surface of said core;
and (c) performing a process to add at least one layer to said
mechanical or chemical prepared surface by a process, said process
being film lamination or hot stamping of the layer from a foil to
the core surface.
5. The composite product claim 1 in which said polymer is a
thermoplastic.
6. The composite product of claim 5 in which the polymer comprises
polyvinyl chloride, polyethylene, polypropylene, ABS, or
styrene.
7. The composite product claim 1 in which the layer is a pattern
that has been transferred from to the core surface from a foil by
hot stamping.
8. The composite product of claim 1 in which the layer is a pattern
on a film that is laminated to the core surface.
9. The composite product of claim 1 comprising more than one of the
layers.
10. The composite product of claim 1 in which the core comprises by
weight less than 92% but greater than 25% polymer.
11. The composite product of claim 1 in which the core comprises by
weight less than 75% but greater than 8% natural fiber
12. The composite product of any of claim 1 in which the layer is
essentially free of abrasive material.
13. The composite product of claim 1 in which the layer provides
visual enhancements and surface design to mimic natural or man made
material surface.
14. The composite product of claim 1 in which the layer comprises a
material that deflects or reflects ultraviolet radiation away from
the core to enhance product resistance to ultraviolet
radiation.
15. The composite product of claim 14 in which the core comprises a
UV resistant pigment.
16. The composite product of claim 1 in which the core, the layer,
or both comprises a substance that resists mold and/or mildew.
17. The composite product of claim 1 in which the layer is a first
layer on a first core surface and the product comprises a second
layer on a core surface opposite the first core surface.
18. The composite product of any of claim 1 in which the layer
reduces water absorption as determined either by at least a 10%
reduction either in weight gain or physical expansion of the
product as compared to the core without the layer, wherein weight
gain or physical expansion are measured by either the room
temperature or elevated temperature test methods of ASTM
D1037-99.
19. The composite product of any of claim 1 in which the product
exhibits extractive bleeding from the natural fiber in the
composite core when subject to moisture that is at least 10% less
than the extractive bleeding of the core without the layer, as
determined by analysis of tannins, tannic acid and their derivative
in a water solution.
20. The composite product of any of claim 1 in which the layer
controls surface temperature by a minimum of 3% as measured using
ASTM D4803-97.
21. The composite product of any of claim 1 in which the layer
increases wear resistance at least 10% compared to the core without
the layer, as measured by ASTM D968-93 Standard Methods for
Abrasion Resistance tests.
22. The composite product of any of claim 1 in which the layer
provides an increase in strength and stiffness compared to the core
without the layer, as measured by ASTM D790-03 Standard Test Method
for Flexural Properties.
23. The composite product of any of claim 1 in which the layer
exhibits color inconsistency of less than 1 .DELTA.E as
demonstrated by ASTM E805-01a Standard Method.
24. The composite product of any of claim 1 in which the layer
reduces color fade or change from environmental exposure, as
compared to the core without the layer, by a minimum of 20% as
measured by ASTM D6864-03ae1 Standard Specification.
Description
RELATED APPLICATION
[0001] This application claims priority under 35 USC .sctn. 119(e)
to U.S. Patent Application Ser. No. 60/641,308, filed on Jan. 1,
2005, the entire contents of which are hereby incorporated by
reference.
TECHNICAL FIELD
[0002] This invention is in the general field of natural
fiber/polymer composites, which are used (for example) in
all-weather products such as decking, railing, fencing, siding,
roofing and other outdoor products.
BACKGROUND
[0003] Wood products used in demanding environments, such as
all-weather floorings, arc subjected to a number of conditions,
including detrimental environmental elements and physical abrasion
and impact that can limit product lifetime and degrade its
appearance. More durable materials, such as natural fiber/polymer
composites, improve product performance and lengthen their useful
life, but they may be aesthetically objectionable or have other
undesirable properties and degradation issues.
[0004] Nishibori U.S. Pat. No. 5,869,138 and U.S. Pat. No.
6,066,367 (each of which is hereby incorporated by reference in its
entirety) disclose a process in which a synthetic wood board is
formed by mixing wood meal with a resin (such as polycarbonate,
nylon, acrylonitrile butadiene styrene (ABS), polyvinyl chloride,
nylon, polyethylene or polypropylene). The mixture is heated,
kneaded and squeezed by extruding it with a screw into a molding
die. The resulting synthetic wood board is then processed by
sanding a surface, applying a colorant, sanding (or grinding) again
to form "wound stripes" with the remaining colorant in a recessed
layer, and then printing a wood pattern on the ground surface, so
that the ink enters the wound stripes.
[0005] Velin et al. U.S. Pat. No. 6,106,654 discloses a decorative
thermosetting laminate with a wear-resistant and a scratch
resistant surface layer. The laminate can be paper impregnated with
a melamine-formaldehyde resin. The top side of the wet paper is
sprinkled with particles to impart abrasion resistance.
[0006] Sjolin et al. U.S. Pat. No. 6,375,777 discloses a process
for making a laminate in which dry paper webs are fed through a
continuous double belt press.
SUMMARY
[0007] The invention generally features a natural fiber/polymer
composite product that includes a core having a surface and a film
or foil layer applied to that core surface. The core comprises at
least one natural fiber and at least one polymer intimately admixed
together to form a composite.
[0008] A first aspect of the invention generally features a natural
fiber/poly,.mer composite having such a core with a mechanically or
chemically prepared (textured) surface. At least one layer is
positioned on the mechanically or chemically prepared core surface.
That layer may be a film laminated onto the mechanically or
chemically prepared core surface, or it may be a layer that has
been hot stamped from a foil onto the mechanically or chemically
prepared core surface.
[0009] In a second aspect of the invention that specifically
features the use of a layer that has been hot stamped from a foil
onto the core surface. Mechanical or chemical preparation of that
core surface is optional.
[0010] In a third aspect of the invention that specifically
features the use of a layer that has laminated onto the core
surface. Mechanical or chemical preparation of that core surface is
optional.
[0011] In a fourth aspect of the invention, the composite product
is made by first extruding at least one natural fiber and at least
one polymer to form a composite core having a smooth surface.
During extrusion or thereafter, a core surface is prepared by
mechanical or chemical preparation. Finally at least one layer is
added to the mechanical or chemical prepared surface, either by
film lamination or by hot stamping the layer from a foil to the
core surface.
[0012] In preferred embodiments of any of the above aspects of the
invention, the polymer is a thermoplastic, such as polyvinyl
chloride, polyethylene, polypropylene, ABS, or styrene. The polymer
may be virgin polymer or recycled polymer. The layer may be a
pattern that has been transferred from to the core surface from a
foil by hot stamping, or it may be a pattern on a film that is
laminated to the core surface.
[0013] More than one of the above-described layers may be included
in the product. For example, one layer may be on a first core
surface and a second layer may be on a core surface opposite the
first core surface.
[0014] Preferably, the core comprises by weight less than 92% but
greater than 25% polymer and less than 75% but greater than 8%
natural fiber.
[0015] The layer may be essentially free of abrasive material.
[0016] The layer may provide visual enhancements and surface design
to mimic natural or man made material surface. It may also include
a material that deflects or reflects ultraviolet radiation away
from the core to enhance product resistance to ultraviolet
radiation. The core may include a UV resistant pigment. The core,
the layer or both may include a substance that resists mold and/or
mildew.
[0017] The layer may provide a number of advantageous physical
characteristics. It may reduce water absorption as determined
either by at least a 10% reduction either in weight gain or
physical expansion of the product as compared to the core without
the layer, wherein weight gain or physical expansion are measured
by either the room temperature or elevated temperature test methods
of ASTM D1037-99. It may exhibit extractive bleeding from the
natural fiber in the composite core when subject to moisture that
is at least 10% less than the extractive bleeding of the core
without the layer, as determined by analysis of tannins, tannic
acid and their derivative in a water solution. It may control
surface temperature by a minimum of 3% as measured using ASTM
D4803-97. It may increase wear resistance at least 10% compared to
the core without the layer, as measured by ASTM D968-93 Standard
Methods for Abrasion Resistance tests. It may provide an increase
in strength and stiffness compared to the core without the layer,
as measured by ASTM D790-03 Standard Test Method for Flexural
Properties. It may exhibit color inconsistency of less than 1-E as
demonstrated by ASTM E805-01a Standard Method. Finally, the product
may reduce color fade or change from environmental exposure, as
compared to the core without the layer, by a minimum of 20% as
measured by ASTM D6864-03ae1 Standard Specification.
[0018] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DETAILED DESCRIPTION
[0019] Extrusion Process for the Core
[0020] Any of a number of extrusion processes may be used to
produce a composite product or core that is then laminated to one
or more decorative surface layers. One such process is direct
extrusion, in which the raw materials (a natural fiber product and
polymer) are added to the extruder, which melts the polymer and
mixes the natural fiber into the polymer them together. The
extruder then forces the molten composite through a die where it
forms a finished product.
[0021] Another process is indirect extrusion, in which the raw
materials (a natural fiber and polymer) are added to the extruder
to melt the polymer and mix it with the fiber to produce a pellet.
This pellet is then re-melted by a second extrusion process that
forces the molten composite through a die where it forms a
profile.
[0022] The finished product produced by either direct or indirect
extrusion becomes the composite core, which is then laminated to a
foil or other thin layer that imparts the desired decorative effect
and physical property enhancements.
[0023] Exemplary extrusion processes are described in greater
detail below with reference to specific examples, without limiting
the invention. Generally, a composite of a polymer and natural
fiber flour is extruded into a shape and then decorated using
transfer foils and wraps. These extruded shapes have use in decking
products, railings, fencing, windows, doors, doorframes, flooring,
and similar applications. The composite material used in these
applications is the result of mixing, blending, or compounding
polymers with fibers such as wood, rice hulls or other fibrous
materials reduced in particle size. The polymers used are
polyethylene, polypropylene, PVC, ABS or styrene. Other
thermoplastic materials capable of being extruded to a desired
shape would also be used for specific applications.
[0024] The raw materials are received in both packaged and bulk
containers and are prepared for processing in a variety of methods.
The fiber flour is received in 40 or 60 mesh. The flour is then
dried to a moisture content of 0-4%, using either drying kilns or
air circulation silos or bins. For kiln drying, the fiber flour is
introduced from either a bulk storage unit or packaged storage
container into an air stream to the kiln, where it is dried then
transferred to dry storage units or containers. Air circulation
drying takes place in larger bulk storage units with the capability
of circulating the fiber using hot air to reduce the moisture
content of the fiber. In addition to the fiber flour and polymer, a
number of additives such as process aids, process stabilizers,
color, anti-fungal agents, blowing agents, weather and aging
protectors, etc. can be added to the blend or compound to obtain
the desired physical properties for any appropriate
application.
[0025] The fiber flour used is typically wood, both hardwood and
softwood. The choice of wood species is dependent on the polymer
used and the intended application. For polyolefin (HDPE)/wood
compounds the wood species is usually oak or maple. These hardwood
species are preferred, because they provide the extruded profile
with a high degree of stiffness, a Modulus of Elasticity of greater
than 500,000 psi. Additionally, maple is preferred over oak,
because maple has a lower tannin content. The lower tannin content
results in less organic acids being produced during the extrusion
process. Further, the lower tannin content allows for higher
extrusion process efficiency and less finished product problems
such as moisture staining on the surface of the extruded product.
For PVC/wood compounds pine is the usual species used. This
softwood offers a smoother exterior surface to the extruded core of
the product. The polymer or polymer compound is blended with the
fiber flour and the additive materials (described above) using
physical mixing units or compounding extruders. The materials are
transferred pneumatically or by vacuum from the bulk storage units
or transferred mechanically/pneumatically from the receiving
containers. All ingredients are then mixed or compounded to a
specific formulation for specific extruding equipment and specific
end products. In some compounding situations, the polymer and
additives are pre-compounded and the fiber flour is introduced as a
secondary step in the blending operation.
[0026] The blended material is processed into a finished composite
material shape or profile using an extruder or can be processed
into a pellet and then reprocessed through a second extrusion
operation to form a shape or profile. The processes are applicable
to single screw extrusion or to twin-screw extruders with either
co-rotating screws or counter-rotating screws. The extruder will
have a temperature profile, temperature settings at various zones
of the extruder, allowing for the melting, final mixing, pumping,
and forcing of the material through the die. The temperature
profile is dependent on the extruder, polymer used, die selection,
and the physical properties required for the finished product.
Whether extruding polyolefin (HDPE)/wood compounds or PVC/wood
compounds a "reverse temperature profile" typically is used. The
highest temperature is at the entry to the extruder to facilitate
melting and mixing, and the temperature is reduced in the barrel
going toward the die. The die temperature reflects the melt
temperature of the extrusion as it exits the extruder. The
combination of materials and equipment determines the specific
temperature profiles. The temperature of the individual heating
zones on the extruder, adapter zone, and die will vary from
88.degree. C. to 240.degree. C. The temperature will be controlled
by zone to give the overall temperature profile required for
optimum extrudability of the blend being used.
[0027] The pressures inside the extruder and at the die are
controlled by feed rates, extruder speed, melt pumping where
applicable, and die design. The feed rate control is determined by
the method of introduction. The raw material is introduced to the
extruder by loss-in-weight feeders that measure the amount of
material fed to the extruder. The material may be transferred from
the feeder to the extruder by gravity. An alternative method
introduces blended material into the extruder using a cramming
device to insure the appropriate amount of material entering the
extruder. Once the raw materials have entered the extruder further
pressure control is accomplished by adjusting the speed of the
extruder screws, measured in revolutions per minute, moving the
material through the barrel of the extruder. If a melt pump is used
the pressure is adjusted further by the speed, rpm, of the melt
pump. The final pressure determination is accomplished by the
internal cavity shape of the die. The pressure in combination with
the temperature profile determines the control of the extruded
shape or profile.
[0028] After the extrudate exits the die it may be calibrated for
final dimensions using a sizing or calibration device to reach
exacting dimensional requirements. Depending on the cooling
characteristics of the material and the shape of the end product
calibration devices may or may not be used. The calibration device
is part of the overall cooling system used to bring the extruded
shape from elevated extrusion temperatures to ambient temperature.
After exiting the die, the extruded shape or profile is introduced
to a cooling medium such as water or air to remove the internal
heat of the shape or profile. In addition to cooling, the
calibration device may also apply vacuum to the extrudate to assist
in the forming of the shape or profile to the desired dimensions.
When employing a sizing or calibration procedure, a pulling device
is used to control the speed of the extrudate through the
calibration system. This technique further allows for the control
of the dimensions of the final shape or profile.
[0029] The cooled and formed shape or profile is cut to desired
lengths using automated cutting devices. The most commonly employed
device is a traveling saw that is calibrated to move at the same
speed as the extrudate thereby giving a consistent length to the
cut shape.
[0030] The formed shape or profile may be further processed using
secondary mechanical operations. These operations may include
molding the part to provide surface alteration or shape tolerance
improvement or embossing the surface with heat pressure devises
that leave surface impressions and visual features.
[0031] As described above, many different profiles are extruded to
create the basic profiles covered by this invention. A very wide
range of materials and formulations have been utilized and tested.
A generic formulation that describes this range of materials and
formulations follows: TABLE-US-00001 Material description Percent
of material in formula Natural fiber 0%-75% (preferably 8-66.5%)
Virgin polymer 0%-92% (preferably 0-71%) Merchant recycled polymer
0%-65% (preferably 0-26%) Internal recycled composite material
0%-65% Lubricants (Internal & external) 2%-7% Blowing agents
0%-6% Process aids & other additives such as compatabilizers
0%-1% Color concentrate 0%-2.5%
[0032] The following formulations are non-limiting examples to
document utilization of high-density polyethylene (HDPE) and
natural fibers to produce the basic composite profile. Those
skilled in the field will understand that numerous other
combinations of formulations appropriate for various product and
applications are covered by this invention. TABLE-US-00002 Weight
Material description of material in formula Hard wood (40 mesh)
(Typical formula) 47% HDPE - Pellets or Powder 27% HDPE - Merchant
recycled 9% Internal recycled HDPE composite material 9% EBS wax 3%
Zinc Stearate 3% Color concentrate 2% Rice Hulls (20/80) (Typical
formula) 47% HDPE - Pellets or Powder 18% HDPE - Merchant recycled
18% Internal recycled HDPE composite material 9% EBS wax 3% Zinc
Stearate 2% Coupling Agent 1% Color concentrate 2%
[0033] The following formulations are examples to document
utilization of polyvinyl chloride (PVC) and natural fibers to
produce the basic composite profile. TABLE-US-00003 Material
description Weight of material in formula Soft wood (60 mesh)
(Typical) 16% PVC - Dry blend or pellets 71% PVC - Merchant
recycled 0.0 Internal recycled PVC composite material 0.0 Other
fillers 4% Process aids 0.0 PVC capstock 9% Rice Hulls (20/80) 24%
PVC - Dry blend or pellets 48% PVC - Merchant recycled 16% Internal
recycled PVC composite material 7% Other fillers 0.0 Blowing agent
5% PVC capstock 0.0
[0034] The following formulations are examples to document
utilization of polypropylene (PP) and natural fibers to produce the
basic composite profile. TABLE-US-00004 Material description Weight
of material in formula Hard wood (40 mesh) 47% PP 34% HDPE -
Merchant recycled 11% Lubricants 7% Color concentrate Less than 1%
Calcium stearate Less than 1%
Applying the Layer
[0035] Once the composite shape or profile has been manufactured,
it then acts as the composite core to which decorative and
protective layer(s) may be hot stamped from a foil or film
laminated, to achieve the improved physical and visual enhancement
over the current inventions. Two methods of decoration/protection
can be utilized to accomplish this process step: a) heat/pressure
transfer of a design from a foil to the core; or b) lamination of a
layer containing a pigmented design to the core.
[0036] The layer may be added either inline and continuous with the
extrusion process, or off line as a secondary operation.
[0037] The layer may provide one or more functional benefits. For
example, the layer may carry a desired pigmented decorative image
and/or variety of performance chemical additives. The foil or
laminate material can be specially designed to transfer a wide
variety of images using highly stable outdoor color pigment for
long-term outdoor exposure. Additionally the foil or laminate
material may contain a variety of product performance enhancing
materials such as heat reflective pigments or materials, mold and
mildew inhibitors, surface hardening materials and others.
[0038] With the inline process, the profile shape exiting the
extrusion process may retain sufficient residual heat to support
the necessary reaction with the foil to adhere the decorative
pigment and chemical additive composition to the profile. In the
offline secondary operation a reheating of the surface through
flame, infrared heat, or direct contact heat transfer will create
sufficient surface temperature. A roll(s) of heat transfer foil is
loaded onto a profile-specific transfer table.
[0039] We now describe the two basic transfer process--hot stamped
foil transfer and film lamination.
[0040] Hot Stamped Foiling
[0041] The first process is the transfer of the layer from a foil
to the composite core using heat and pressure.
[0042] The surface of the extruded part may be (but is not required
that it be) prepared mechanically or chemically, or using both
methods, to accept the transfer of decorative materials from the
foil. This preparation creates an improved surface in which to
adhere the hot stamp foil. The mechanical preparation may include
molding, planing, sanding, or some other method of mechanical
abrasion to the intended decorative surface. These techniques
expose additional natural fiber and reduce the surface content of
polyethylene or other extrusion process materials that impede foil
adherence. As an alternative procedure, chemical abrasion may be
used to accomplish similar results, using a chemical such as (but
not limited to) acid wash or corona discharge for polyethylene or
other polymer core materials.
[0043] Once the surface is prepared the foil is placed on the
surface and with the application of heat the decorative materials
are transferred to the surface of the composite core. The heat of
application also activates the adhesive allowing the decorative
materials to bond to the surface of the composite core. As the
decorative materials are transferred the carrier foil is removed
and discarded.
[0044] The foil is shaped to the profile of the core using a series
of rollers that force the foil to cover the shape of the composite
core profile.
[0045] Subsequent to the application of the foil a topcoat, or
protective layer, may be applied for enhanced physical properties.
The choice of topcoat materials, polyurethane or acrylics for
example, is dependent on the end use of the decorated product.
[0046] Film Lamination
[0047] A second decorative method involves the use of a film
laminated to the composite core. The film wrap is a polymeric sheet
material which has had the decorative materials and patterns
applied to it.
[0048] The composite core profile surface may be ( but is not
required that it be) prepared in the same manner as described
above. For example, surface of the extruded part is prepared
mechanically or chemically, or using both methods, to accept the
lamination of the film wrap material. This preparation creates an
improved surface in which to adhere the film wrap. The mechanical
preparation may include molding, planing, sanding or some other
method of mechanical abrasion to the intended decorative surface.
These techniques expose additional natural fiber and reduce the
surface content of polyethylene or other extrusion process
materials that impede film wrap adherence. As an alternative
procedure, chemical abrasion may be used to accomplish similar
results using chemical such as but not limited to acid wash or
corona discharge for polyethylene or other polymer core
materials.
[0049] After the composite core has been mechanically or chemically
readied and primed for the film wrap, the profile passes through a
wrapping device. This device takes the film wrap from a coil then
applies the adhesive to the wrap material. In a continuous process
the film wrap is then passed over the composite core. Again using
equipment using a series of rollers the film wrap is shaped to the
composite core profile.
[0050] The film wrap may incorporate in addition to its decorative
elements an integral topcoat material for physical property
enhancement. This integrated element may be polyurethane, acrylic
or other protective materials.
[0051] If the film wrap integrates only the decorative elements,
then the wrapped product next has a topcoat applied to enhance the
physical properties of the entire decorative system. The topcoat
can be polyurethane, acrylic, or other protective material that
will impart better physical properties to the wrapped finished
part.
[0052] The topcoat may be spray applied or hot melt applied. If
spray applied, the wrapped product will pass through a spray
applicator and then may or may not pass through a curing device
such as ultra-violet radiation curing.
[0053] If the topcoat is hot melt applied, then a layer of
polyurethane is applied to flat surfaces of the decorated part. The
cure process for this type of material is time dependent and could
take several days depending on the hot melts topcoat chosen for a
specific end-use application for the completed finished
product.
[0054] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *