U.S. patent application number 12/113656 was filed with the patent office on 2008-11-06 for encapsulated plastic panel and method of making the same.
Invention is credited to Steven M. Gasworth, Sunitha K. Grandhee, Wilfried Hedderich, Keith D. Weiss.
Application Number | 20080272613 12/113656 |
Document ID | / |
Family ID | 39645582 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080272613 |
Kind Code |
A1 |
Weiss; Keith D. ; et
al. |
November 6, 2008 |
ENCAPSULATED PLASTIC PANEL AND METHOD OF MAKING THE SAME
Abstract
An economical method of manufacturing a plastic glazing panel
having an encapsulation for aesthetic purposes and to enhance the
sealing of the glazing panel to the vehicle is presented. This
economical method includes the steps of forming forming a plastic
panel having an A-side and B-side; printing an opaque border from
an ink with the border being in contact with the B-side of the
panel and substantially encircling the perimeter of the panel;
curing the ink of the opaque border; applying a weatherable layer
on the printed border and the plastic panel; curing the weatherable
layer; depositing an abrasion resistant layer on the weatherable
layer; placing the plastic panel into a mold having a soft gasket;
injecting an elastomeric material to form an encapsulation that
substantially encircles the perimeter of the plastic panel and
encompasses the A-side; B-side and edge of the plastic panel; and
removing the plastic panel from the mold.
Inventors: |
Weiss; Keith D.; (Fenton,
MI) ; Gasworth; Steven M.; (Novi, MI) ;
Grandhee; Sunitha K.; (Novi, MI) ; Hedderich;
Wilfried; (Hilden, DE) |
Correspondence
Address: |
EXATEC;C/O BRINKS HOFER GILSON & LIONE
524 South Main Street, Suite 200
Ann Arbor
MI
48104
US
|
Family ID: |
39645582 |
Appl. No.: |
12/113656 |
Filed: |
May 1, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60915274 |
May 1, 2007 |
|
|
|
Current U.S.
Class: |
296/146.1 ;
264/271.1 |
Current CPC
Class: |
B32B 2255/10 20130101;
B29L 2031/30 20130101; B32B 2605/006 20130101; B32B 2307/712
20130101; C09D 11/101 20130101; B29C 45/14434 20130101; B32B 27/365
20130101; B29C 2795/00 20130101; B60J 1/00 20130101; B32B 38/00
20130101; B62D 65/06 20130101; B29K 2995/0025 20130101; C09D 11/104
20130101; Y10T 428/24777 20150115; B29C 45/14336 20130101; B60J
7/00 20130101; B29C 70/763 20130101; B32B 2255/20 20130101; B32B
2255/26 20130101; B32B 2255/28 20130101; B32B 38/145 20130101; B32B
27/304 20130101; Y10T 428/239 20150115; B32B 2307/41 20130101; B32B
27/08 20130101; B32B 2307/584 20130101; B29L 2031/778 20130101;
B29C 45/14811 20130101; B29K 2995/002 20130101; B29K 2995/0087
20130101; B32B 2305/72 20130101 |
Class at
Publication: |
296/146.1 ;
264/271.1 |
International
Class: |
B60J 1/00 20060101
B60J001/00; B29B 11/08 20060101 B29B011/08 |
Claims
1. A plastic glazing panel for use as an automotive window or
sunroof, the glazing panel comprising: a substantially transparent
plastic panel having an A-side, B-side, and an edge; an opaque
border in contact with the B-side of the plastic panel and that
substantially encircles the perimeter of the plastic panel; a
weatherable layer in contact with the opaque border and the plastic
panel; an abrasion resistant layer in contact with the weatherable
layer; and an encapsulation in contact with the abrasion resistant
layer and that substantially encircles the perimeter of the plastic
panel.
2. The plastic glazing panel of claim 1, wherein the encapsulation
encompasses the A-side, B-side, and edge of the plastic panel.
3. The plastic glazing panel of claim 1, wherein the encapsulation
is one selected from the group of polyvinyl chloride (PVC),
thermoplastic elastomers, urethanes, and thermoplastic olefins.
4. The plastic glazing panel of claim 1, further comprising a
plastic film in contact with the opaque border and the B-side of
the plastic panel.
5. The plastic glazing panel of claim 4, wherein the plastic film
is in contact with the weatherable layer.
6. The plastic glazing panel of claim 1, wherein the plastic panel
is made from a thermoplastic or thermoset polymeric resin.
7. The plastic glazing panel of claim 6, wherein the polymeric
resin is one selected from polycarbonate, acrylic, polyarylate,
polyester, polysulfone, and a copolymer or mixture thereof.
8. The plastic glazing panel of claim 1, wherein the opaque border
is an ink that includes a binder selected as one from a
polyester-based, polycarbonate-based, and acrylate-based
binder.
9. The plastic glazing panel of claim 1, wherein the weatherable
layer is one selected from silicones, polyurethanes, acrylics,
polyesters, epoxies, and a copolymer or mixture thereof.
10. The plastic glazing panel of claim 9, wherein the weatherable
layer uses ultraviolet absorbing (UVA) molecules to protect the
plastic panel from UV radiation.
11. The plastic glazing panel of claim 9, wherein the weatherable
layer is made up of a primer and a topcoat.
12. The plastic glazing panel of claim 1, wherein the abrasion
resistant layer is one selected from aluminum oxide, barium
fluoride, boron nitride, hafnium oxide, lanthanum fluoride,
magnesium fluoride, magnesium oxide, scandium oxide, silicon
monoxide, silicon dioxide, silicon nitride, silicon oxy-nitride,
silicon oxy-carbide, hydrogenated silicon oxy-carbide, silicon
carbide, tantalum oxide, titanium oxide, tin oxide, indium tin
oxide, yttrium oxide, zinc oxide, zinc selenide, zinc sulfide,
zirconium oxide, zirconium titanate, and a mixture or blend
thereof.
13. The plastic glazing panel of claim 12, wherein the silicon
oxy-carbide abrasion resistant layer has a composition ranging from
SiO.sub.x to SiO.sub.xC.sub.yH.sub.z.
14. A method of manufacturing a plastic glazing panel for use as an
automotive window or sunroof, the method comprising the steps of:
forming a plastic panel having an A-side and B-side; printing an
opaque border from an ink with the border being in contact with the
B-side of the panel and substantially encircling the perimeter of
the panel; curing the ink of the opaque border; applying a
weatherable layer on the printed border and the plastic panel;
curing the weatherable layer; depositing an abrasion resistant
layer on the weatherable layer; placing the plastic panel into a
mold having a soft gasket; injecting an elastomeric material to
form an encapsulation that substantially encircles the perimeter of
the plastic panel; and removing the plastic panel from the
mold.
15. The method of manufacturing a plastic glazing panel of claim
14, wherein the step of injecting an elastomeric material forms an
encapsulation that encompasses the A-side, B-side, and edge of the
plastic panel.
16. The method of manufacturing a plastic glazing panel of claim
14, further comprising the step of applying an adhesion promoter on
top of the abrasion resistant layer encircling the B-side perimeter
of the plastic panel prior to placing the plastic panel into the
mold to form the encapsulation.
17. The method of manufacturing a plastic glazing panel of claim
16, further comprising the step of heating the plastic panel on the
A-side and B-side of the plastic panel in close temporal proximity
to activate the adhesion promoter without substantially distorting
the shape of the window.
18. A method of manufacturing the plastic glazing panel of claim
14, wherein the step of forming the plastic includes a method
selected from injection molding, blow molding, compression molding,
thermal forming, vacuum forming, and cold forming.
19. A method of manufacturing the plastic glazing panel of claim
14, wherein the ink printing step includes a method selected from
screen printing, pad printing, or ink jet printing.
20. A method of manufacturing the plastic glazing panel of claim
14, wherein the ink curing step uses a method selected as one of
air drying, UV absorption, thermal absorption, condensation
addition, thermally driven entanglement, cross-linking induced by
cationic or anionic species, or a combination thereof
21. A method of manufacturing the plastic glazing panel of claim
14, wherein the step of applying the weatherable layer uses a
method selected as one of flow coating, spray coating, curtain
coating, dip coating, or spin coating.
22. A method of manufacturing a plastic glazing panel of claim 14,
wherein the step of curing the weatherable layer includes a
mechanism selected as one of air drying, UV absorption, thermal
absorption, condensation addition, thermally driven entanglement,
cross-linking induced by cationic or anionic species, and a
combination thereof.
23. A method of manufacturing the plastic glazing panel of claim
14, wherein the step of depositing an abrasion resistant layer uses
a vacuum deposition technique.
24. A method of manufacturing the plastic glazing panel of claim
22, wherein the step of depositing an abrasion resistant layer uses
a vacuum deposition technique selected from plasma-enhanced
chemical vapor deposition (PECVD), expanding thermal plasma PECVD,
plasma polymerization, photochemical vapor deposition, ion beam
deposition, ion plating deposition, cathodic arc deposition,
sputtering, evaporation, hollow-cathode activated deposition,
magnetron activated deposition, activated reactive evaporation,
thermal chemical vapor deposition, and any known sol-gel coating
process.
25. A method of manufacturing the plastic glazing panel of claim
14, wherein the steps of printing an opaque border from an ink and
curing the ink on the plastic panel is replaced with the steps of
printing an opaque border from an ink on to a plastic film; curing
the ink on the plastic film; and forming and adhering the opaque
border and the plastic film to the B-side of the plastic panel so
that the opaque border substantially encircles the perimeter of the
plastic panel.
Description
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 60/915,274 filed on May 1, 2007, entitled
"ENCAPSULATED PLASTIC WINDOW," the entire contents of which are
incorporated herein by reference.
FIELD
[0002] This invention relates to plastic glazing panels that are
encapsulated to promote sealing and appearance when used as a
window or sunroof.
BACKGROUND
[0003] For a number of years, car manufacturers have favored window
encapsulation for the sealing of automotive glass. Such
encapsulation technology includes molding an elastomeric gasket
directly onto the surface of the glass. These gaskets are typically
made from a variety of materials including thermoplastic elastomers
(TPE) and polyvinyl chloride (PVC), as well as cross-linked
polyurethanes applied via reaction injection molding (RIM). The
encapsulation process for a conventional glass window may be
described as including the steps of applying a primer or adhesion
promoter to the perimeter of the one side of the window; applying
heat to this side of the window to activate the primer; placing the
window in a mold; injecting the thermoplastic elastomer onto the
primer and the adjacent surface of the window; removing the window
from the mold, and trimming any excess elastomeric material that
has accumulated at the interface between the window and the
encapsulation. Such excess or scrap elastomeric material is known
by one skilled-in-the-art of encapsulation as "flash" material. The
trimming of the "flash" material is typically done with a sharp
object, such as a knife or razor blade. The encapsulated glass
window is then fixed into the opening of a vehicle typically
through the use of an adhesive system, such as the urethane
BETASEAL.TM. system offered by Dow Automotive, Auburn Hills,
Mich.
[0004] The use of plastic glazing panels provides several issues
for the use of conventional encapsulation technology. First,
plastic glazing panels are typically coated with a weatherable
coating system, such as the acrylic primer (e.g., SHP401 and
SHP470) and silicone hard-coat (e.g., AS4000 and AS4700) systems
offered by Momentive Performance Materials, Wilton, Conn. in order
for the glazing panel to survive exposure to the environment.
Unfortunately the surface properties associated with a silicone
hard-coat is such that most conventional encapsulation materials
can not effectively adhere, thereby, creating a weakened interface
that will cause the plastic glazing after being fixed to a vehicle
to prematurely fail. The known remedy for this situation has been
to apply the encapsulation to the bare plastic panel (e.g., no
protective coatings). However, this solution requires a masking
step before applying the weatherable coating and a de-masking step
after the weatherable coating is cured. The addition of these two
steps increases the costs associated with manufacturing an
encapsulated plastic glazing panel.
[0005] Second, plastic glazing systems are not as hard as a
conventional glass window. Thus the trimming of any "flash"
material created by the encapsulation process will result in
irreversible damage to the coating system of the plastic glazing
panel. This damage will ultimately result in premature degradation
of the properties exhibited by the plastic glazing panel.
[0006] Finally, plastic glazing panels exhibit different thermal
expansion characteristics than glass windows. Thus heating the
surface of the plastic glazing panel to activate any adhesion
promoter used to facilitate adhesion between the plastic glazing
panel and the encapsulation will cause substantial distortion to
the shape of the window. Such a distortion will result in the
operator having difficulty in securing the window into the mold
during the encapsulation process. Thus this process will suffer
from an increase in cycle time and an overall loss in
productivity.
[0007] Therefore, there is a need in the industry to develop a
plastic glazing panel and a process in which the plastic glazing
panel can be encapsulated without degrading the properties
exhibited by the plastic glazing panel or affecting cycle time or
productivity.
SUMMARY
[0008] An economical method of manufacturing a plastic glazing
panel having an encapsulation for aesthetic purposes and to enhance
the sealing of the glazing panel to the vehicle is presented. This
economical method includes the steps of forming a plastic panel
having an A-side and B-side; printing an opaque border from an ink
with the border being in contact with the B-side of the panel and
substantially encircling the perimeter of the panel; curing the ink
of the opaque border; applying a weatherable layer on the printed
border and the plastic panel; curing the weatherable layer;
depositing an abrasion resistant layer on the weatherable layer;
placing the plastic panel into a mold having a soft gasket;
injecting an elastomeric material to form an encapsulation that
substantially encircles the perimeter of the plastic panel and
encompasses the A-side, B-side, and edge of the plastic panel; and
finally removing the plastic panel from the mold. The use of a soft
gasket in the mold reduces or eliminates the occurrence of "flash"
material being generated at the edge of the interface between the
encapsulation and the plastic glazing panel.
[0009] Optionally the step of applying an adhesion promoter on top
of the abrasion resistant layer encircling the B-side perimeter of
the plastic panel may take place prior to placing the plastic panel
into the mold to form the encapsulation. The plastic panel is then
heated on the A-side and B-side of the plastic panel in close
temporal proximity to activate the adhesion promoter without
substantially distorting the shape of the window.
[0010] In another embodiment of the present invention, the steps of
printing an opaque border from an ink and curing the ink on the
plastic panel is replaced with the steps of printing an opaque
border from an ink on to a plastic film; curing the ink on the
plastic film; and forming and adhering the opaque border and the
plastic film to the B-side of the plastic panel so that the opaque
border substantially encircles the perimeter of the plastic
panel.
[0011] In another embodiment of the present invention the
encapsulated plastic glazing panel comprises a substantially
transparent plastic panel having an A-side, B-side, and an edge; an
opaque border in contact with the B-side of the plastic panel and
that substantially encircles the perimeter of the plastic panel; a
weatherable layer in contact with the opaque border and the plastic
panel; an abrasion resistant layer in contact with the weatherable
layer; and an encapsulation in contact with the abrasion resistant
layer and that substantially encircles the perimeter of the plastic
panel and encompasses the A-side, B-side, and edge of the plastic
panel.
[0012] In another embodiment of the present invention, the plastic
glazing panel further comprises a plastic film that has one side of
the film in contact with the opaque border and the B-side of the
plastic panel and the other side of the film in contact with the
weatherable layer.
[0013] In another embodiment of the present invention, the
weatherable layer may include a single layer or multiple layers,
such as a primer and a topcoat. The weatherable layer uses
ultraviolet absorbing (UVA) molecules to protect the plastic panel
from UV radiation.
[0014] In another embodiment of the present invention, the abrasion
resistant layer is deposited using a vacuum deposition technique.
One example of an abrasion resistant layer includes, but is not
limited to, silicon oxy-carbide having a composition ranging from
SiO.sub.x to SiO.sub.xC.sub.yH.sub.z.
[0015] Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and specific examples are intended for purposes of
illustration only and are not intended to limit the scope of the
present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way.
[0017] FIG. 1 is a depiction of an automobile window according to
the principles of the present invention.
[0018] FIG. 2 is a schematic of a manufacturing process for a
plastic glazing panel according to one embodiment of the present
invention.
[0019] FIG. 3 is a diagrammatic representation of a cross-section
of a glazing panel from FIG. 1 according to one embodiment of the
present invention.
DETAILED DESCRIPTION
[0020] The following description is merely exemplary in nature and
is in no way intended to limit the present disclosure or its
application or uses. It should be understood that throughout the
description and drawings, corresponding reference numerals indicate
like or corresponding parts and features.
[0021] The present invention provides a plastic glazing panel and
an economical method of manufacturing such a glazing panel that
includes the application of encapsulation that substantially
encircles the perimeter of the window. The plastic glazing panel
also includes a decorative printed border and a protective coating
system to provide a high level of weatherability and abrasion
resistance. Referring to FIG. 1, a plastic glazing panel may be
used as an automotive fixed side window 10. The window 10 is shown
having a substantially transparent viewing area 15, a printed
opaque border 20 encompassing the transparent viewing area 15, and
an encapsulation 25 encircling the perimeter of the glazing panel
10. One skilled-in-the-art of automotive design will realize that
the plastic glazing panel of the present invention can be used for
other automotive windows, such as a backlite, sunroof, and movable
side windows, among others.
[0022] Referring to FIG. 2, an economical manufacturing process may
generally be defined by first forming 30 a plastic panel; then
printing 35 an opaque border with an ink on the plastic panel;
followed by curing 40 the printed ink; applying 45 a weatherable
layer onto the printed plastic panel; curing 50 the weatherable
layer, depositing 55 an abrasion resistant layer onto the
weatherable layer, placing 60 the panel into a mold; forming 65 the
encapsulation by injecting an encapsulating material to the outer
perimeter of the glazing panel, and then removing 70 the
encapsulated glazing panel from the mold.
[0023] The transparent plastic panel may be formed 30 into a
window, e.g., vehicle window, from plastic pellets or sheets
through the use of any known technique to those skilled in the art,
such as extrusion, molding, which includes injection molding, blow
molding, and compression molding, or thermoforming, which includes
thermal forming, vacuum forming, and cold forming. It is to be
noted that the forming 30 of a window using plastic sheet may occur
prior to printing as shown in FIG. 2, after printing 35 and curing
40 of the ink, or after application 45 and curing 50 of the
weatherable coating without falling beyond the scope or spirit of
the present invention. The use of plastic pellets to form 30 the
plastic panel is done prior to printing 35 the opaque pattern.
[0024] An opaque border may be defined as a substantially opaque
ink printed or applied 35 for decorative purposes and/or to hide or
mask other vehicle components (e.g., adhesives). This opaque border
may be applied 35 to the periphery of the transparent substrate to
form a solid masking border. The opaque border may further include
a fade-out pattern to transition the border into the viewing region
of the window. The fade-out pattern may incorporate a variety of
shapes of variable size including dots, rectangles (lines),
squares, and triangles, among others.
[0025] In one embodiment of the present invention, the opaque
border and can be printed 35 onto the surface of the plastic panel
via screen printing. Other known methods of printing 35 the opaque
border on the plastic panel may also be utilized when deemed
appropriate. A non-inclusive list of other known printing methods
include pad printing, membrane image transfer printing, cylindrical
printing, digital printing, robotic dispensing, mask/spray, ink-jet
printing, and the like. The thickness of the printed ink may range
from about 2 micrometers to about 1 mil (25.4 micrometers) with
about 6 to 12 micrometers being preferred.
[0026] Once the ink is printed 35, drying or curing 40 should be
thorough in order to ensure that any retained solvent is removed
from the print. The inks may be thermally cured by being exposed to
an elevated temperature for a period of time, cured upon exposure
to UV radiation, or via a combination thereof. The thickness of the
cured ink print is typically about 4 .mu.m to 20 .mu.m with between
about 6 .mu.m to 18 .mu.m being preferred.
[0027] The weatherable layer is applied 45 to the printed panel by
dip coating, flow coating, spray coating, curtain coating, spin
coating, or any other techniques known to those skilled-in-the-art.
The thickness of the weatherable layer may range from about 2
micrometers to several mils (1 mil=25.4 micrometers), with about 6
micrometers to 1 mil being preferred. The weatherable layer may
then be cured 50 using a mechanism selected as one of air drying,
UV absorption, thermal absorption, condensation addition, thermally
driven entanglement, cross-linking induced by cationic or anionic
species, or a combination thereof.
[0028] The weatherable layer is over-coated via the deposition 55
of an abrasion resistant layer. This abrasion resistant layer may
be either comprised of one layer or a combination of multiple
inter-layers of variable composition. The abrasion resistant layer
is applied by any vacuum deposition technique known to those
skilled-in-the-art, including but not limited to plasma-enhanced
chemical vapor deposition (PECVD), expanding thermal plasma PECVD,
plasma polymerization, photochemical vapor deposition, ion beam
deposition, ion plating deposition, cathodic arc deposition,
sputtering, evaporation, hollow-cathode activated deposition,
magnetron activated deposition, activated reactive evaporation,
thermal chemical vapor deposition, and any known sol-gel coating
process.
[0029] In one embodiment of the present invention, a specific type
of PECVD process used to deposit the abrasion resistant layers
comprising an expanding thermal plasma reactor is preferred. This
specific process (called hereafter as an expanding thermal plasma
PECVD process) is described in detail in U.S. patent application
Ser. No. 10/881,949 (filed Jun. 28, 2004) and U.S. patent
application Ser. No. 11/075,343 (filed Mar. 8, 2005), the entirety
of both being hereby incorporated by reference. In an expanding
thermal plasma PECVD process, a plasma is generated via applying a
direct-current (DC) voltage to a cathode that arcs to a
corresponding anode plate in an inert gas environment. The pressure
near the cathode is typically higher than about 150 Torr, e.g.,
close to atmospheric pressure, while the pressure near the anode
resembles the process pressure established in the plasma treatment
chamber of about 20 mTorr to about 100 mTorr. The near atmospheric
thermal plasma then supersonically expands into the plasma
treatment chamber.
[0030] The reactive reagent for the expanding thermal plasma PECVD
process may comprise, for example, octamethylcyclotetrasiloxane
(D4), tetramethyldisiloxane (TMDSO), hexamethyldisiloxane (HMDSO),
vinyl-D4 or another volatile organosilicon compound. The
organosilicon compounds are oxidized, decomposed, and polymerized
in the arc plasma deposition equipment, typically in the presence
of oxygen and an inert carrier gas, such as argon, to form an
abrasion resistant layer.
[0031] The plastic glazing panel is then placed 60 into a mold
whose cavity is formed to the shape of the glazing panel. The mold
is equipped with a soft gasket to seal the substantially
transparent viewing portion of the glazing panel from the
subsequent injection of the encapsulation material that forms 65
the encapsulation. The gasket provides an effective stop to the
flow of the encapsulation material, thereby, eliminating the
formation of any "flash" material at the edge of the interface
between the encapsulation and the glazing panel. The existence of
"flash" material is found to cause the formation of wrinkles or
blemishes in the abrasion resistant layer of the plastic glazing.
In addition, the trimming or removal of "flash" material via the
use of a sharp instrument, such as a knife or razor blade, can
damage the abrasion resistant layer and the weatherable layer of
the plastic glazing panel, as well as possibly the opaque border
and the underlying plastic panel itself.
[0032] Prior to placing 60 the plastic glazing panel into the mold,
an adhesion promoter may optionally be used to enhance adhesion
between the abrasion resistant layer and the encapsulation.
However, the conventional means of applying and curing or
activating the primer is unacceptable for use with a plastic
glazing system. The thermal expansion characteristics of a plastic
glazing panel are such that applying heat onto one surface of the
plastic panel results in reversible expansion or distortion of the
shape of the panel. This expansion or distortion results in
difficulty in holding the glazing panel by any mechanical means
(e.g., robotic, etc.) and in placing 60 the glazing panel into the
mold. The application of heat on both surfaces of the glazing panel
via substantially simultaneous application is found to minimize or
eliminate the occurrence of this distortion. The application of
heat to both sides of the window may be accomplished through the
use of any means known to one skilled-in-the-art, including, but
not limited to, IR heating or forced air heating.
[0033] Referring now to FIG. 3, a cross-section of a plastic
glazing panel according to one embodiment of the present invention
is shown. The plastic panel 15 may be comprised of any
thermoplastic or thermoset polymeric resin. The polymeric resins
include, but are not limited to, polycarbonate, acrylic,
polyarylate, polyester, and polysulfone, as well as copolymers and
mixtures thereof. In order to function appropriately as a window
and to allow for the dual curing of the printed ink, the plastic
panel 15 is substantially transparent.
[0034] The printed ink 20 may be comprised of a thermally curable
ink or a UV curable ink. A thermally curable ink may include a
polyester-based binder, a polycarbonate-based binder, or a mixture
thereof. A UV curable ink may include a mixture of various
multifunctional acrylate oligomers and monomers along with a
photoinitiator. Examples of inks include Exatec.RTM. PIX (Exatec
LLC, Wixom, Mich.) and DXT-1599 (Coates Screen, St. Charles, Ill.),
among others.
[0035] The ink 20 may further comprise other additives, such as
colorants (e.g., pigments and/or dyes), fillers, surfactants,
defoamers, tackifiers, adhesion promoters, viscosity promoters,
weatherability additives. Examples of pigments include, but are not
limited to, carbon black, colored organic pigments, and metal oxide
pigments; while suitable dyes include various direct dyes, acidic
dyes, basic dyes, and/or reactive dyes. Various surfactants and
defoamers may include any organic, organosilicon, and silicone
molecules that are well known to one skilled-in-the-art to function
in such a capacity. In order to enhance the weatherability of the
printed and cured ink, the ink may include hindered amines or UV
absorber molecules.
[0036] The weatherable layer 75 may be comprised of, but not
limited to, silicones, polyurethanes, acrylics, polyesters,
polyurethane-acrylates, and epoxies, as well as mixtures or
copolymers thereof. The weatherable layer 75 preferably includes
ultraviolet (UV) absorbing molecules, such as
hydroxyphenyltriazine, hydroxybenzophenones,
hydroxylphenylbenzotriazoles, hydroxyphenyltriazines,
polyaroylresorcinols,
2-(3-triethoxysilylpropyl)-4,6-dibenzoylresorcinol) (SDBR),
4,6-dibenzoylresorcinol (DBR), and cyanoacrylates, among others to
protect the underlying plastic panel and printed ink from
degradation caused by exposure to the outdoor environment.
[0037] The weatherable layer 75 may be comprised of one homogenous
layer or multiple sub-layers, such as a primer and a topcoat. A
primer typically aids in adhering the topcoat to the plastic panel.
The primer for example may include, but not be limited to,
acrylics, polyesters, epoxies, and copolymers and mixtures thereof.
Similarly, the topcoat may include, but not be limited to,
polymethylmethacrylate, polyvinylidene fluoride, polyvinylfluoride,
polypropylene, polyethylene, polyurethane, silicone,
polymethacrylate, polyurethane-acrylates, polyacrylate,
polyvinylidene fluoride, silicone hardcoat, and mixtures or
copolymers thereof. One specific example of a weatherable layer 75
comprising multiple sub-layers is the combination of an acrylic
primer (SHP401 or SHP470, Momentive Performance Materials,
Waterford, N.Y.; or SHP-9X, Exatec LLC, Wixom, Mich.) with a
silicone hard-coat (AS4000 or AS4700, Momentive Performance
Materials; or SHX, Exatec LLC).
[0038] A variety of additives may be added to the weatherable layer
75, e.g., to either or both the primer and the topcoat, such as
colorants (tints), Theological control agents, mold release agents,
antioxidants, and IR absorbing or reflecting pigments, among
others. The type of additive and the amount of each additive is
determined by the performance required by the plastic glazing panel
to meet the specification and requirements for use as a window.
[0039] The abrasion resistant layer 80 may be comprised of aluminum
oxide, barium fluoride, boron nitride, hafnium oxide, lanthanum
fluoride, magnesium fluoride, magnesium oxide, scandium oxide,
silicon monoxide, silicon dioxide, silicon nitride, silicon
oxy-nitride, silicon oxy-carbide, hydrogenated silicon oxy-carbide,
silicon carbide, tantalum oxide, titanium oxide, tin oxide, indium
tin oxide, yttrium oxide, zinc oxide, zinc selenide, zinc sulfide,
zirconium oxide, zirconium titanate, or a mixture or blend thereof.
Preferably, the abrasion resistant layer 80 is comprised of a
composition ranging from SiO.sub.x to SiO.sub.xC.sub.yH.sub.z
depending upon the amount of carbon and hydrogen atoms that remain
in the deposited layer. This preferred silicon oxy-carbide layer
provides the surface properties suitable for the subsequent
adherence of an encapsulation material.
[0040] The encapsulation 25 may be comprised of any known
encapsulation material known to one skilled-in-the-art including,
but not limited to, polyvinyl chloride (PVC), thermoplastic
elastomers, urethanes, and thermoplastic olefins. Optionally an
adhesion promoter 85 may be used to enhance the adhesion between
the encapsulation and the abrasion resistant layer. Examples of
such adhesion promoters include acrylic polymers, urethanes,
organosilanes, and chlorinated polyolefin polymers, among
others.
[0041] The encapsulated glazing panel may be fixed or secured to an
opening in a vehicle through any means known to one
skilled-in-the-art. Such means include, but are not limited to, the
use of clips or fasteners and bonding via the use of adhesives.
[0042] Before an encapsulated glazing panel can be used on a
vehicle, the glazing panel must pass a series of tests specified by
the original equipment manufacturers (OEMs) to be done using either
the finished, encapsulated plastic glazing panels or smaller test
plaques or coupons that represent the encapsulated glazing panel.
One very demanding series of tests used with coupons is specified
by Honda Motor Company as specification number N/K. In this test,
coupons of the encapsulated glazing system are exposed to various
conditions and then the encapsulation is pulled away from the
plastic glazing panel under both shear and peel loads. In order to
pass each test in this series of tests, the failure mode observed
upon separation of the encapsulation from the glazing panel must be
100% cohesive failure of the encapsulation. Any loss of adhesion at
any interface within the plastic glazing panel (e.g., between the
plastic panel and the ink, the ink and weatherable layer, or
weatherable layer and abrasion resistant layer) or between the
glazing panel and the encapsulation would constitute a failure.
[0043] An example of a standard set of tests performed on finished,
encapsulated glazing panels is specified by General Motors as test
specification number GM-3611. Similar to the coupon testing, the
full glazing panels in this series of tests are exposed to various
conditions and the cohesive strength of the encapsulation evaluated
by performing both peel- and shear-oriented pull tests. In order to
pass each test in this series, the failure mode observed for the
separation of the encapsulation and plastic glazing panel must be
100% cohesive failure of the encapsulation. Any loss of adhesion at
any interface within the plastic glazing panel or between the
glazing panel and encapsulation would constitute a failure. The
actual conditions to which full encapsulated glazing panels and
test coupons are exposed are shown in Tables 1 and 2,
respectfully.
[0044] The following specific examples are given to illustrate the
invention and should not be construed to limit the scope of the
invention.
EXAMPLE 1
Testing of Encapsulated Plastic Glazing Panels
[0045] Multiple plastic glazing panels were formed using Lexan.RTM.
polycarbonate sheet (SABIC Innovative Plastics, Pittsfield, Mass.)
to fit a General Motor's Trailblazer SUV as a fixed side window.
The formed plastic panel was printed with an opaque border using a
thermally curable ink (Exatec.RTM. PIX, Exatec LLC, Wixom, Mich.),
which was subsequently cured according to the manufacturer's
specification. A weatherable layer comprised of an acrylic primer
(SHP401, Momentive Performance Materials, Waterford, N.Y.) and a
silicon hard-coat (SHX, Exatec LLC) was applied over the opaque
border and plastic panel. On top of the weatherable layer, a
silicon oxy-carbide abrasion resistant layer was deposited using
expanding arc plasma enhanced chemical vapor deposition. The
resulting plastic glazing panel is known as the Exatec.RTM. 500
glazing system (Exatec LLC, Wixom, Mich.).
[0046] An adhesion promoter was then applied around the perimeter
of the glazing panel in-line with the opaque border. The adhesion
promoter was cured or activated by simultaneously heating both
sides of the glazing panel using an IR heating source. The glazing
panel was placed into a mold and polyvinyl chloride (Vi-Chem
Corporation, Grand Rapids, Mich.) injected to form the
encapsulation.
[0047] The encapsulated plastic glazing panels were then tested
according to General Motors' GM-3611 specification. As shown in
Table 1, the encapsulated glazing panels were observed to pass all
of the tests listed in this specification by resulting in 100%
cohesive failure of the PVC encapsulation. This example
demonstrates that an encapsulated plastic glazing panel prepared
according to one embodiment of the present invention can pass
stringent OEM requirements for use as a window in a vehicle.
TABLE-US-00001 TABLE 1 Test Result Exposure Conditions .sub.(Pass =
100% cohesive) Initial Pull Ambient Temperature PASS Humidity
Resistance 38.degree. C., 100% relative PASS humidity for 7 days
Heat Resistance 70.degree. C. for 14 days PASS Thermal Cycle C
Heat, humidity, Cold PASS cycling for 8 weeks
EXAMPLE 2
Testing of Encapsulated Glazing Coupons
[0048] Multiple plastic glazing coupons were formed using
Lexan.RTM. polycarbonate sheet (SABIC Innovative Plastics,
Pittsfield, Mass.) to be substantially flat. The formed plastic
coupons were printed with an opaque border using a thermally
curable ink (Exatec.RTM. PIX, Exatec LLC, Wixom, Mich.), which was
subsequently cured according to the manufacturer's specification. A
weatherable layer comprised of an acrylic primer (SHP401, Momentive
Performance Materials, Waterford, N.Y.) and a silicon hard-coat
(SHX, Exatec LLC) was applied over the each opaque border and
plastic coupon. On top of the weatherable layer, a silicon
oxy-carbide abrasion resistant layer was deposited using expanding
arc plasma enhanced chemical vapor deposition. The resulting
plastic glazing coupons represented a glazing system known as the
Exatec.RTM. 500 glazing system (Exatec LLC, Wixom, Mich.).
[0049] An adhesion promoter was then applied around the perimeter
of each glazing coupon in-line with the opaque border. The adhesion
promoter was cured or activated by simultaneously heating both
sides of the glazing coupons. The glazing coupons were placed into
a mold and polyvinyl chloride (Vi-Chem Corporation, Grand Rapids,
Mich.) injected to form the encapsulation.
[0050] The encapsulated plastic glazing coupons were then tested
according to Honda Motor Company's N/K specification. As shown in
Table 2, the encapsulated glazing coupons were observed to pass all
of the tests listed in this specification by resulting in 100%
cohesive failure of the PVC encapsulation. This example
demonstrates that an encapsulated plastic glazing panel prepared
according to one embodiment of the present invention can pass
stringent OEM requirements for use as a window in a vehicle.
TABLE-US-00002 TABLE 2 Test Result Exposure Conditions .sub.(Pass =
100% cohesive) Initial Pull Ambient Temperature PASS Humidity
Resistance 50.degree. C., 95% relative PASS humidity for 90 days
Heat Resistance 90.degree. C. for 90 days PASS Thermal Cycle C
Heat, humidity, Cold PASS cycling for 8 weeks Hot Water Resistance
80.degree. C. for 100 hours PASS Hot Pull Test at 90.degree. C.
PASS Cold Pull Test at -40.degree. C. PASS Cataplasma Per IES60.014
protocol PASS Xenon Arc 2000 hours per SAE PASS J1960 protocol
EXAMPLE 3
Adhesion Differences in Weatherable and Abrasion Resistant
Layers
[0051] Multiple plastic glazing panels were formed using Lexan.RTM.
polycarbonate sheet (SABIC Innovative Plastics, Pittsfield, Mass.)
into a substantially flat panel. The formed plastic panel was
printed with an opaque border using a thermally curable ink
(Exatec.RTM. PIX, Exatec LLC, Wixom, Mich.), which was subsequently
cured according to the manufacturer's specification. A weatherable
layer comprised of an acrylic primer (SHP-9.times., Exatec LLC,
Wixom, Mich.) and a silicon hard-coat (SHX, Exatec LLC) was applied
over the opaque border and plastic panel. On about one-half of the
panels, a silicon oxy-carbide abrasion resistant layer was
deposited using expanding arc plasma enhanced chemical vapor
deposition. The resulting plastic glazing panel is known as the
Exatec.RTM. 900 glazing system (Exatec LLC, Wixom, Mich.). The
glazing panels having the outer layer as the weatherable layer
(e.g., no deposited abrasion resistant layer) is representative of
the situation of the outer surface being a silicon hard-coat.
[0052] Adhesion promoters and a urethane adhesive bead was applied
to the perimeter of the glazing panels having a silicon hard-coat
surface and the glazing panels having an outer surface of an
abrasion resistant layer. The adhesion promoters and urethane
adhesive is known as the BETASEAL.TM. system offered by Dow
Automotive, Auburn Hills, Mich. The adhesion promoters and urethane
adhesive was cured according to the manufacturer's
specification.
[0053] The glazing panels were then subjected to a Cataplasma test
known to one skilled-in-the-art as Dow Automotive AG, Test Method
No. 039E--Cataplasma Treatment. The Cataplasma test is also
incorporated as one of the tests performed in the Honda Motor
Company N/K test specification. The Cataplasma test exposes the
plastic glazing panel along with cured adhesive beads applied to
the surface of the glazing panel to high humidity at an elevated
temperature followed by a low temperature shock (i.e., wrapping the
glazing panel for 7 days in wet cotton at 70.degree. C. followed by
3 hrs at -20.degree. C.). Upon completion of the testing, and after
being equilibrated at room temperature (about 23.degree. C.) the
adhesive bead is pulled on each test panel and the degree of
cohesive failure of the adhesive is examined. In order for a
printed plastic glazing panel to pass the Cataplasma test, there
must be greater than 75% cohesive failure of the adhesive.
Therefore, for the plastic glazing panel to pass the above test,
the entire glazing panel, i.e., plastic panel 15/cured ink 20/cured
weatherable layer 75/abrasion resistant layer 80 (if present) must
exhibit a high level of hydrolytic stability at different
temperatures and moisture conditions.
[0054] The inventors observed that the plastic glazing panels have
a silicon hard-coat outer surface in contact with the adhesion
promoters and urethane failed the test with less than about 2%
cohesive failure of the urethane. Rather poor adhesion between the
silicon hard-coat and the adhesion promoters and urethane caused
the failure. On the other hand, all samples tested that
incorporated an outer surface of the abrasion resistant layer were
found to pass the test with greater than 75% cohesive failure of
the urethane. This example demonstrates the difference in
performance between a silicon hard-coat surface and the surface of
the abrasion resistant layer. Similar results are obtainable when
the adhesion promoters and urethane are replaced with similar
adhesion promoters and an encapsulation.
[0055] A person skilled in the art will recognize from the previous
description that modifications and changes can be made to the
present disclosure without departing from the scope of the
disclosure as defined in the following claims. A person skilled in
the art will further recognize that the various measurements and
tests described are standard measurements that can be obtained by a
variety of different test methods. The test methods described in
the examples represents only one available method to obtain each of
the required measurements.
* * * * *