U.S. patent application number 12/369771 was filed with the patent office on 2009-09-17 for device capable of thermally cooling while electrically insulating.
This patent application is currently assigned to E. I. DU PONT DE NEMOURS AND COMPANY. Invention is credited to Brian C. AUMAN, Carl HAEGER, Philip Roland LACOURT, Mark Elliott MCALEES, Stanley Duane MERRITT, George Wyatt PREJEAN, Harland Lee TATE.
Application Number | 20090229809 12/369771 |
Document ID | / |
Family ID | 41061735 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090229809 |
Kind Code |
A1 |
AUMAN; Brian C. ; et
al. |
September 17, 2009 |
DEVICE CAPABLE OF THERMALLY COOLING WHILE ELECTRICALLY
INSULATING
Abstract
The present disclosure relates to a device for thermally cooling
while electrically insulating. The device contains a first adhesive
layer, polyimide substrate, a second adhesive layer and a heat
sink. The first adhesive layer and the second adhesive layer are a
vinyl or acrylic polymer. The polyimide substrate has at least two
polyimide layers. The polyimide layers are derived from at least
one aromatic dianhydride and at least one aromatic diamine. The
adhesive layers and the polyimide layers may contain thermally
conductive fillers, light absorbing pigments or mixtures of
both.
Inventors: |
AUMAN; Brian C.;
(Pickerington, OH) ; HAEGER; Carl; (Reynoldsburg,
OH) ; LACOURT; Philip Roland; (Chillicothe, OH)
; MCALEES; Mark Elliott; (Circleville, OH) ;
MERRITT; Stanley Duane; (Bear, DE) ; PREJEAN; George
Wyatt; (ORANGE, TX) ; TATE; Harland Lee;
(Golden, CO) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1122B, 4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Assignee: |
E. I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
41061735 |
Appl. No.: |
12/369771 |
Filed: |
February 12, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61036506 |
Mar 14, 2008 |
|
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|
Current U.S.
Class: |
165/185 |
Current CPC
Class: |
H01L 2924/01013
20130101; B32B 2307/302 20130101; H01L 2924/0103 20130101; B32B
2255/10 20130101; H01L 2924/01047 20130101; B32B 2264/10 20130101;
B32B 2307/206 20130101; H01L 2924/01006 20130101; B32B 27/304
20130101; H01L 2224/73253 20130101; H01L 2924/01024 20130101; B32B
27/20 20130101; H01L 24/33 20130101; H01L 2924/01004 20130101; H01L
2924/19041 20130101; Y02E 10/50 20130101; B32B 2307/30 20130101;
H01L 2924/01005 20130101; B32B 2255/26 20130101; B32B 2307/71
20130101; H01L 23/3737 20130101; B32B 27/322 20130101; H01L 31/048
20130101; B32B 7/12 20130101; H01L 31/052 20130101; H01L 2924/01023
20130101; H01L 2924/19042 20130101; H01L 2924/19043 20130101; B32B
15/08 20130101; B32B 2264/102 20130101; B32B 27/18 20130101; B32B
27/30 20130101; B32B 2307/306 20130101; B32B 2307/714 20130101;
B32B 2457/12 20130101; H01L 31/0481 20130101; H01L 2924/01033
20130101; B32B 27/281 20130101; B32B 27/308 20130101; H01L 24/30
20130101; B32B 27/08 20130101; H01L 2924/01074 20130101; H01L
2924/01082 20130101; H01L 2924/14 20130101; B32B 27/16 20130101;
B32B 15/20 20130101; B32B 27/306 20130101 |
Class at
Publication: |
165/185 |
International
Class: |
F28F 7/00 20060101
F28F007/00 |
Claims
1. A device for thermally cooling while electrically insulating
comprising: A. a first adhesive layer having a top surface and a
bottom surface, the first adhesive layer bottom surface being
directly bonded to a polyimide substrate, the first adhesive layer
comprising an amount from 68 to 98 weight percent vinyl or acrylic
polymer; B. a polyimide substrate comprising at least a first
polyimide layer and a second polyimide layer wherein: i. the first
polyimide layer and the second polyimide layer are directly bonded
to each other; the first polyimide layer and the second polyimide
layer are the same or different, and provide thermal conduction and
electrical insulation properties, ii. the first polyimide layer and
the second polyimide layer each comprise an amount from 40 to 90
weight percent polyimide, the polyimide being derived from at least
one aromatic dianhydride and at least one aromatic diamine, the
aromatic diamine being at least 80 mole percent of the total moles
of diamine incorporated into the polyimide and the aromatic
dianhydride being at least 80 mole percent of the total moles of
dianhydride incorporated into the polyimide, and iii. the first
polyimide layer and the second polyimide layer each further
comprise 10 to 50 weight percent thermally conductive filler, and 0
to 20 weight percent light absorbing pigment; C. a second adhesive
layer having a top surface and a bottom surface, the second
adhesive layer top surface being directly bonded to the polyimide
substrate; the second adhesive layer comprising an amount from 68
to 98 weight percent vinyl or acrylic polymer; D. a metal heat sink
having a top surface and a bottom surface, the heat sink top
surface being directly bonded to the second adhesive layer bottom
surface.
2. A device in accordance with claim 1, wherein the first adhesive
layer and the second adhesive layer additionally comprise a filler
selected from thermally conductive filler, light absorbing pigment
and mixtures thereof.
3. A device in accordance with claim 1 or 2, wherein the first
adhesive layer and second adhesive layers are selected from a group
consisting of: ethylene vinyl acetate copolymer with adhesion
promotor, ethylene vinyl acetate glycidyl acrylate terpolymer,
ethylene vinyl acetate glycidyl methacrylate terpolymer, ethylene
alkyl acrylate copolymers with adhesion promotor, ethylene alkyl
methacrylate copolymers with adhesion promotor, ethylene glycidyl
acrylate, ethylene glycidyl methacrylate, ethylene alkyl acrylate
glycidyl acrylate terpolymer, ethylene alkyl methacrylate glycidyl
acrylate terpolymer, ethylene alkyl acrylate maleic anhydride
terpolymers, ethylene alkyl methacrylate maleic anhydride
terpolymers ethylene alkyl acrylate glycidyl methacrylate
terpolymers, ethylene alkyl methacrylate glycidyl methacrylate
terpolymers, alkyl acrylate acrylonitrile acrylic acid terpolymers,
alkyl acrylate acrylonitrile methacrylic acid terpolymers, ethylene
acrylic acid copolymer including salts thereof, ethylene
methacrylic acid copolymer including salts thereof, alkyl acrylate
acrylonitrile glycidyl methacrylate terpolymers, alkyl methacrylate
acrylonitrile glycidyl methacrylate terpolymers, alkyl acrylate
acrylonitrile glycidyl acrylate terpolymers, alkyl methacrylate
acrylonitrile glycidyl acrylate terpolymers, polyvinyl butyral,
ethylene alkyl acrylate methacrylic acid terpolymers including
salts thereof, ethylene alkyl methacrylate methacrylic acid
terpolymers including salts thereof, ethylene alkyl acrylate
acrylic acid terpolymers including salts thereof mixtures thereof,
ethylene alkyl methacrylate acrylic acid terpolymers including
salts thereof, ethylene ethyl hydrogen maleate, ethylene alkyl
acrylate ethyl hydrogen maleate, ethylene alkyl methacrylate ethyl
hydrogen maleate, and mixtures thereof.
4. A device in accordance with claim 1, wherein the polyimide
substrate additionally comprises at least one fluoropolymer
adhesive layer having a top layer and a bottom layer wherein the
fluoropolymer adhesive top layer is attached to the first polyimide
layer and the fluoropolymer adhesive bottom layer is attached to
the second polyimide layer.
5. A device in accordance with claim 4, wherein the fluoropolymer
adhesive layer is selected from tetrafluoroethylene
hexafluoropropylene copolymer, tetrafluoroethylene perfluoroalkoxy
copolymer, tetrafluoroethylene ethylene copolymer, polyvinyl
fluoride and mixtures thereof.
6. A device in accordance with claim 4, wherein the fluoropolymer
adhesive layer additionally comprises a thermally conductive
filler.
7. A device in accordance with claim 4, wherein the polyimide
substrate first polyimide layer and second polyimide layer comprise
two or more polyimide layers.
8. A device in accordance with claim 1, wherein the aromatic
dianhydride is selected from a group consisting of pyromellitic
dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride,
3,3',4,4'-benzophenone tetracarboxylic dianhydride,
4,4'-oxydiphthalic anhydride, 3,3',4,4'-diphenyl sulfone
tetracarboxylic dianhydride,
2,2-bis(3,4-dicarboxyphenyl)1,1,1,3,3,3-hexafluoropropane
dianhydride and mixtures thereof; and wherein the aromatic diamine
is selected from a group consisting of 3,4'-diaminodiphenyl ether,
1,3-bis-(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether,
1,4-diaminobenzene, 1,3-diaminobenzene and mixtures thereof.
9. A device in accordance with claims 1, 2 or 6 wherein the
thermally conductive filler is selected from a group consisting of
aluminum oxide, boron nitride coated aluminum oxide, granular
aluminum oxide, fumed aluminum oxide, silicon dioxide, granular
silicon dioxide, fumed silicon dioxide, silicon carbide, aluminum
nitride, aluminum oxide coated aluminum nitride, silicon dioxide
coated aluminum nitride, titanium dioxide, boron nitride, cubic
boron nitride, hexagonal boron nitride, diamond, beryllium oxide,
talc, zinc oxide and mixtures thereof.
10. A device in accordance with claims 1 or 2, wherein the light
absorbing pigment is selected from a group consisting of carbon
black, titanium dioxide, benzotriazoles, benzophenones, hindered
amines and mixtures thereof.
11. A device in accordance with claim 1 wherein the first adhesive
layer and the second adhesive layer thickness are each from 6.25 to
75 microns.
12. A device in accordance with claim 1 wherein the polyimide
substrate thickness is from 8 to 150 microns.
13. A device in accordance with claim 1 wherein the polyimide
substrate thickness is from 12.5 to 125 microns.
14. A device in accordance with claim 4 wherein the fluoropolymer
adhesive layer thickness is from 1.25 to 12.5 microns.
15. A device in accordance with claim 1 further comprising
photovoltaic cell directly bonded to the first adhesive layer top
surface.
16. A device for thermally cooling while electrically insulating
comprising: A. a first adhesive layer having a top surface and a
bottom surface, the first adhesive layer bottom surface being
directly bonded to a polyimide substrate, the first adhesive layer
comprising an amount from 68 to 98 weight percent vinyl or acrylic
polymer; B. a polyimide substrate comprising at least a first
polyimide layer and a second polyimide layer wherein: i. the first
polyimide layer and the second polyimide layer are directly bonded
to each other; the first polyimide layer and the second polyimide
layer are the same or different, and provide thermal conduction and
electrical insulation properties, ii. the first polyimide layer and
the second polyimide layer each comprise an amount from 40 to 90
weight percent polyimide, the polyimide being derived from at least
one aromatic dianhydride and at least one aromatic diamine, the
aromatic diamine being at least 50 mole percent of the total moles
of diamine incorporated into the polyimide and the aromatic
dianhydride being at least 50 mole percent of the total moles of
dianhydride incorporated into the polyimide, and iii. the first
polyimide layer and the second polyimide layer each further
comprise 5 to 50 weight percent thermally conductive filler, and 0
to 20 weight percent light absorbing pigment; C. a second adhesive
layer having a top surface and a bottom surface, the second
adhesive layer top surface being directly bonded to the polyimide
substrate; the second adhesive layer comprising an amount from 68
to 98 weight percent vinyl or acrylic polymer; D. a metal heat sink
having a top surface and a bottom surface, the heat sink top
surface being directly bonded to the second adhesive layer bottom
surface.
Description
FIELD OF DISCLOSURE
[0001] The present disclosure relates generally to multilayer
device for thermal dissipation and electrical insulation. More
specifically, the device comprises a filled polyimide film that can
be bonded to a metal heat sink on one side and to an electronic
component on the other, thereby electrically insulating the
electronic component while also conducting heat away from the
circuit.
BACKGROUND OF THE DISCLOSURE
[0002] In the field of electronic components, including
photovoltaic cells, both heat dissipation and electrical insulation
are becoming increasingly important. Integrated circuits are
increasingly being manufactured at smaller feature dimensions and
higher densities, resulting in an increased need for thermal
dissipation and electrical insulation. Similarly, thermal
dissipation and electrical insulation are also important for
photovoltaic systems, which tend to require a highly (electrically)
insulated environment for collecting and distributing electrical
current and also tend to lose operational efficiency with
increasing temperature.
[0003] U.S. Pat. No. 5,691,567 to Lo, et al., describes a polyimide
tape used to connect a heat sink to a lead frame by means of a die
attach adhesive. Such a polyimide tape system is described in the
background discussion in Lo, and Lo then teaches against such a
polyimide tape system.
[0004] A need exists for a device that: i. provides acceptable bond
strength under elevated temperatures and humidity; ii. has
acceptable electrical insulation properties; iii. can withstand
relatively high voltages, iv. resists degradation due to light; and
v. also has acceptable thermal conductivity.
SUMMARY
[0005] The present disclosure is directed to a device for thermally
cooling while electrically insulating. The device contains a first
adhesive layer, polyimide substrate, a second adhesive layer and a
heat sink. The first adhesive layer and the second adhesive layer
have 68 to 98 weight percent vinyl or acrylic polymer. The
polyimide substrate has at least two polyimide layers having 40 to
90 weight percent polyimide where the polyimide is derived from at
least one aromatic dianhydride and at least one aromatic
diamine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0006] The present disclosure is directed to a device for thermally
cooling while electrically insulating. In one embodiment, the
device has:
[0007] i. a first adhesive layer having a top surface and a bottom
surface. The first adhesive layer bottom surface being directly
bonded to a polyimide substrate,
[0008] ii. a polyimide substrate having at least a first polyimide
layer and a second polyimide layer where the first polyimide layer
and the second polyimide layer are directly bonded to each
other.
[0009] iii. a second adhesive layer having a top surface and a
bottom surface. The second adhesive layer top surface being
directly bonded to the polyimide substrate.
[0010] iv. a metal heat sink having a top surface and a bottom
surface, the heat sink top surface being directly bonded to the
second adhesive layer bottom surface.
[0011] The device is well suited for cooling and insulating
electrical components. The term "electrical components" herein
denotes but is not limited to integrated circuit devices plus other
active and passive components like resistors, capacitors,
inductors, transistors, diodes, and photovoltaic cells. The device
of the present disclosure is particularly well suited for
photovoltaic cells that utilize a light concentrator. In some
embodiments, the semiconducting layer of a photovoltaic cell is
directly bonded to the first adhesive layer top surface. The term
"bonded", "bonding" or any other variation thereof is synonymous
with "adhered" or "adhesion" and the terms may be used
interchangeably. The devices of the present disclosure tend to: i.
maintain good bond strength under high temperatures, ii. provide
useful electrical insulation, iii. provide high voltage resistance,
iv. provide useful resistance to degradation under exposure to
light, and v. provide adequate thermal conductivity.
Adhesive Layers
[0012] The present disclosure comprises a first adhesive layer and
a second adhesive layer. In some embodiments, the first adhesive
layer and second adhesive layer are the same material. In some
embodiments, they are different materials. The first adhesive layer
and the second adhesive layer have an amount between (and
optionally including) any two of the following weight percentages
of vinyl or acrylic polymer: 68, 70, 72, 74, 76, 78, 80, 82, 84,
86, 88, 90, 92, 94, 96 and 98 weight percent (vinyl or acrylic
polymer). In some embodiments, the adhesive polymer is
crosslinkable. In another embodiment, the adhesive polymer is
extrudable or coatable. In some embodiments, the first and second
adhesive layers are selected from a group consisting of: [0013]
ethylene vinyl acetate copolymer with adhesion promoter, [0014]
ethylene vinyl acetate glycidyl acrylate terpolymer, [0015]
ethylene vinyl acetate glycidyl methacrylate terpolymer, [0016]
ethylene alkyl acrylate copolymers with adhesion promoter, [0017]
ethylene alkyl methacrylate copolymers with adhesion promoter,
[0018] ethylene glycidyl acrylate, [0019] ethylene glycidyl
methacrylate, [0020] ethylene alkyl acrylate glycidyl acrylate
terpolymer, [0021] ethylene alkyl methacrylate glycidyl acrylate
terpolymer, [0022] ethylene alkyl acrylate maleic anhydride
terpolymers, [0023] ethylene alkyl methacrylate maleic anhydride
terpolymers [0024] ethylene alkyl acrylate glycidyl methacrylate
terpolymers, [0025] ethylene alkyl methacrylate glycidyl
methacrylate terpolymers, [0026] alkyl acrylate acrylonitrile
acrylic acid terpolymers including salts thereof, [0027] alkyl
acrylate acrylonitrile methacrylic acid terpolymers including salts
thereof, [0028] ethylene acrylic acid copolymer including salts
thereof, [0029] ethylene methacrylic acid copolymer including salts
thereof, [0030] alkyl acrylate acrylonitrile glycidyl methacrylate
terpolymers, [0031] alkyl methacrylate acrylonitrile glycidyl
methacrylate terpolymers, [0032] alkyl acrylate acrylonitrile
glycidyl acrylate terpolymers, [0033] alkyl methacrylate
acrylonitrile glycidyl acrylate terpolymers, polyvinyl butyral,
[0034] ethylene alkyl acrylate methacrylic acid terpolymers
including salts thereof, [0035] ethylene alkyl methacrylate
methacrylic acid terpolymers including salts thereof, [0036]
ethylene alkyl acrylate acrylic acid terpolymers including salts
thereof mixtures thereof, [0037] ethylene alkyl methacrylate
acrylic acid terpolymers including salts thereof, [0038] ethylene
ethyl hydrogen maleate, [0039] ethylene alkyl acrylate ethyl
hydrogen maleate, [0040] ethylene alkyl methacrylate ethyl hydrogen
maleate, and mixtures thereof.
[0041] In some embodiments, the first and second adhesive layers
contain other additives known to one of skill in the art. The
ethylene vinyl acetate copolymer (EVA) of this disclosure includes
formulated EVA which contains an organic peroxide such as TBEC
(OO-tert-butyl O-(2ethylhexyl)monoperoxycarbonate), a UV absorber
such as the benzotriazole type or benzophenone type, a hindered
amine light stabilizer, primary or secondary antioxidants or both,
an organo functional silane adhesion promoter. In another
embodiment, the formulated EVA is BixCure from Bixby International
Corporation, Newburyport, Mass. or Etimex Vistasolar 486/486.1 from
Etimex Vistasolar, D-89165 Dietenheim Germany.
[0042] There is a practical limit to the thickness of the adhesive
layers. The adhesive layers should be thin enough to not adversely
impact thermal dissipation, thus allowing heat to pass efficiently
to the heat sink. Adhesive layers should also provide reliable
bonding between the polyimide substrate and the heat sink, as well
as any electrical component to which the first adhesive top layer
is bonded, at elevated temperatures and humidity. In some
embodiments, the first adhesive layer and the second adhesive layer
thickness are each between (and optionally including) any two of
the following thicknesses: 6.25, 7, 8, 9, 10, 15, 20, 25, 30, 35,
40, 45, 50, 55, 60, 65, 70 and 75 microns. In some embodiments, the
adhesive layers provide bond strength of at least 370 g/cm (2.07
PLI) and preferably higher than 740 g/cm (4.14 PLI). The bond
strength should also be maintained at a level of at least 370 g/cm
over the life of the component under conditions of elevated
temperature and humidity. These conditions will depend on the
particular component and the application in which it is used.
[0043] In some embodiments, the first adhesive layer and the second
adhesive layer additionally comprise a filler selected from
thermally conductive filler, light absorbing pigment and mixtures
thereof. In some embodiments, the first adhesive layer and the
second adhesive layer contain the same thermally conductive fillers
or light absorbing pigments or mixtures thereof. In another
embodiment, the first adhesive layer and the second adhesive layer
contain different thermally conductive fillers or light absorbing
pigments or mixtures thereof. In yet another embodiment, the
thermally conductive filler and the light absorbing pigment may be
the same material when the material can perform both functions.
[0044] In some embodiments, the adhesive layers may include
additional additives such as, antioxidants, crosslinking agents,
adhesion promoters and other common additives known in the art. In
some embodiments, an organo functional silane adhesion promoter is
used. In another embodiment, an alkyl titanate adhesion promoter is
used.
[0045] The adhesive layers of the present disclosure have an
advantage over pressure sensitive adhesives used in the prior art.
The adhesive layers of the present disclosure will have better heat
resistance and cohesive strength. In addition, the adhesive layers
of the present disclosure are integrated films, thus are more
suitable for a continuous manufacturing process.
Polyimide Substrate
[0046] The polyimide substrates of the present disclosure provide
an electrically insulating layer to prevent undesired electrical
communication between an electrical component and the heat sink.
The polyimide substrate of the present disclosure allows high
electrical insulation at high voltages, resists degradation under
exposure to light and provides acceptable thermal conduction,
generally allowing an electronic component to operate at desired
temperatures. This is particularly true when the electrical
component is a photovoltaic cell utilizing a light concentrator.
Temperatures can reach several hundreds degrees centigrade at peak
operating conditions under highly concentrated light. High
voltages, according to the present disclosure, are voltages in
excess of 1000 volts DC or in some applications, greater than 2000
volts DC.
[0047] The polyimide substrate of the present disclosure has at
least two polyimide layers, a first polyimide layer and a second
polyimide layer. In some embodiments, the first polyimide layer and
the second polyimide layer are directly bonded to each other. In
some embodiments, the first polyimide layer and the second
polyimide layer are the same polyimide or different. The polyimide
layers provide thermal conduction and electrical insulation
properties. The first polyimide layer and the second polyimide
layer each comprise an amount between (and optionally including)
any two of the following weight percentages of polyimide: 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90 and 95 weight percent polyimide.
In one embodiment, the polyimide is derived from at least one
aromatic dianhydride and at least one aromatic diamine, the
aromatic diamine being at least 50 mole percent of the total moles
of diamine incorporated into the polyimide and the aromatic
dianhydride being at least 50 mole percent of the total moles of
dianhydride incorporated into the polyimide. In another embodiment,
the aromatic diamine is at least 80 mole percent of the total moles
of diamine incorporated into the polyimide and the aromatic
dianhydride being at least 80 mole percent of the total moles of
dianhydride incorporated into the polyimide. In some embodiments,
the polyimide is a wholly aromatic polyimide. In some embodiments,
the polyimide layers may be corona or plasma treated to aid in
bonding.
[0048] In some embodiments, the aromatic dianhydride polyimide
precursor of the present disclosure is selected from a group
consisting of: [0049] 1. pyromellitic dianhydride (PMDA); [0050] 2.
3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA); [0051] 3.
3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA); [0052]
4. 4,4'-oxydiphthalic anhydride (ODPA); [0053] 5.
3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA);
[0054] 6. 2,2-bis(3,4-dicarboxyphenyl)1,1,1,3,3,3-hexafluoropropane
dianhydride (6FDA); [0055] 7.
4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA);
[0056] 8. 2,3,6,7-naphthalene tetracarboxylic dianhydride; [0057]
9. 1,2,5,6-naphthalene tetracarboxylic dianhydride; [0058] 10.
1,4,5,8-naphthalene tetracarboxylic dianhydride; [0059] 11.
2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride; [0060]
12. 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride;
[0061] 13. 2,3,3',4'-biphenyl tetracarboxylic dianhydride; [0062]
14. 2,2',3,3'-biphenyl tetracarboxylic dianhydride; [0063] 15.
2,3,3',4'-benzophenone tetracarboxylic dianhydride; [0064] 16.
2,2',3,3'-benzophenone tetracarboxylic dianhydride; [0065] 17.
2,2-bis(3,4-dicarboxyphenyl)propane dianhydride; [0066] 18.
1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride; [0067] 19.
1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride; [0068] 20.
bis-(2,3-dicarboxyphenyl)methane dianhydride; [0069] 21.
bis-(3,4-dicarboxyphenyl)methane dianhydride; [0070] 22.
4,4'-(hexafluoroisopropylidene)diphthalic anhydride; [0071] 23.
bis-(3,4-dicarboxyphenyl)sulfoxide dianhydride; [0072] 24.
tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride; [0073] 25.
pyrazine-2,3,5,6-tetracarboxylic dianhydride; [0074] 26.
thiophene-2,3,4,5-tetracarboxylic dianhydride; [0075] 27.
phenanthrene-1,8,9,10-tetracarboxylic dianhydride; [0076] 28.
perylene-3,4,9,10-tetracarboxylic dianhydride; [0077] 29.
bis-1,3-isobenzofurandione; [0078] 30.
bis-(3,4-dicarboxyphenyl)thioether dianhydride; [0079] 31.
bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylicdianhydride; [0080]
32. 2-(3',4'-dicarboxyphenyl)5,6-dicarboxybenzimidazole
dianhydride; [0081] 33.
2-(3',4'-dicarboxyphenyl)5,6-dicarboxybenzoxazole dianhydride;
[0082] 34. 2-(3',4'-dicarboxyphenyl)5,6-dicarboxybenzothiazole
dianhydride; [0083] 35. bis-(3,4-dicarboxyphenyl)2,5-oxadiazole
1,3,4-dianhydride; [0084] 36.
bis-2,5-(3',4'-dicarboxydiphenylether)1,3,4-oxadiazole dianhydride;
[0085] 37. bis-2,5-(3',4'-dicarboxydiphenylether)1,3,4-oxadiazole
dianhydride; [0086] 38.
5-(2,5-dioxotetrahydro)-3-methyl-3-cyclohexene-1,2-dicarboxylic
anhydride; [0087] 39. trimellitic anhydride
2,2-bis(3',4'-dicarboxyphenyl)propane dianhydride; [0088] 40.
1,2,3,4-cyclobutane dianhydride; [0089] 41.
2,3,5-tricarboxycyclopentylacetic acid dianhydride; and mixtures
thereof.
[0090] In some embodiments, the aromatic diamine of the present
disclosure is selected from a group consisting of: [0091] 1.
4,4'-diaminodiphenyl ether (4,4'-ODA); [0092] 2.
3,4'-diaminodiphenyl ether (3,4'-ODA); [0093] 3.
1,3-bis-(4-aminophenoxy)benzene (APB-134 or RODA); [0094] 4.
1,3-bis-(3-aminophenoxy)benzene (APB-133); [0095] 5.
1,2-diaminobenzene (OPD); [0096] 6. 1,3-diaminobenzene (MPD);
[0097] 7. 1,4-diaminobenzene (PPD); [0098] 8. 2,2
bis-(4-aminophenyl)propane; [0099] 9. 4,4'-diaminodiphenyl methane;
[0100] 10. 4,4'-diaminodiphenyl sulfide (4,4'-DDS); [0101] 11.
3,3'-diaminodiphenyl sulfone (3,3'-DDS); [0102] 12.
4,4'-diaminodiphenyl sulfone; [0103] 13.
1,2-bis-(4-aminophenoxy)benzene; [0104] 14.
1,2-bis-(3-aminophenoxy)benzene; [0105] 15.
1,4-bis-(4-aminophenoxy)benzene; [0106] 16.
1,4-bis-(3-aminophenoxy)benzene; [0107] 17. 1,5-diaminonaphthalene;
[0108] 18. 1,8-diaminonaphthalene; [0109] 19.
2,2'-bis(trifluoromethyl)benzidine; [0110] 20.
4,4'-diaminodiphenyldiethylsilane; [0111] 21.
4,4'-diaminodiphenylsilane; [0112] 22.
4,4'-diaminodiphenylethylphosphine oxide; [0113] 23.
4,4'-diaminodiphenyl-N-methyl amine; [0114] 24.
4,4'-diaminodiphenyl-N-phenyl amine; [0115] 25.
2,5-dimethyl-1,4-diaminobenzene; [0116] 26.
2-(trifluoromethyl)-1,4-phenylenediamine; [0117] 27.
5-(trifluoromethyl)-1,3-phenylenediamine; [0118] 28.
2,2-Bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane (BDAF); [0119]
29. 2,2-bis(3-aminophenyl) 1,1,1,3,3,3-hexafluoropropane; [0120]
30. benzidine; [0121] 31. 4,4'-diaminobenzophenone; [0122] 32.
3,4'-diaminobenzophenone; [0123] 33. 3,3'-diaminobenzophenone;
[0124] 34. m-xylylene diamine; [0125] 35.
bisaminophenoxyphenylsulfone; [0126] 36.
4,4'-isopropylidenedianiline; [0127] 37.
N,N-bis-(4-aminophenyl)methylamine; [0128] 38.
N,N-bis-(4-aminophenyl)aniline [0129] 39.
3,3'-dimethyl-4,4'-diaminobiphenyl; [0130] 40.
4-aminophenyl-3-aminobenzoate; [0131] 41. 2,4-diaminotoluene;
[0132] 42. 2,5-diaminotoluene; [0133] 43. 2,6-diaminotoluene;
[0134] 44. 2,4-diamine-5-chlorotoluene; [0135] 45.
2,4-diamine-6-chlorotoluene; [0136] 46.
4-chloro-1,2-phenylenediamine; [0137] 47.
4-chloro-1,3-phenylenediamine; [0138] 48.
2,4-bis-(beta-amino-t-butyl)toluene; [0139] 49.
bis-(p-beta-amino-t-butyl phenyl)ether; [0140] 50.
p-bis-2-(2-methyl-4-aminopentyl)benzene; [0141] 51. 1
-(4-aminophenoxy)-3-(3-aminophenoxy)benzene; [0142] 52.
1-(4-aminophenoxy)-4-(3-aminophenoxy)benzene; [0143] 53.
2,2-bis-[4-(4-aminophenoxy)phenyl]propane (BAPP); [0144] 54.
bis-[4-(4-aminophenoxy)phenyl]sulfone (BAPS); [0145] 55.
2,2-bis[4-(3-aminophenoxy)phenyl]sulfone (m-BAPS); [0146] 56.
4,4'-bis-(aminophenoxy)biphenyl (BAPB); [0147] 57.
bis-(4-[4-aminophenoxy]phenyl)ether (BAPE); [0148] 58.
2,2'-bis-(4-aminophenyl)-hexafluoropropane (6F diamine); [0149] 59.
bis(3-aminophenyl)-3,5-di(trifluoromethyl)phenylphosphine oxide
[0150] 60. 2,2'-bis-(4-phenoxy aniline)isopropylidene; [0151] 61.
2,4,6-trimethyl-1,3-diaminobenzene; [0152] 62.
4,4'-diamino-2,2'-trifluoromethyl diphenyloxide; [0153] 63.
3,3'-diamino-5,5'-trifluoromethyl diphenyloxide; [0154] 64.
4,4'-trifluoromethyl-2,2'-diaminobiphenyl; [0155] 65.
4,4'-oxy-bis-[(2-trifluoromethyl)benzene amine]; [0156] 66.
4,4'-oxy-bis-[(3-trifluoromethyl)benzene amine]; [0157] 67.
4,4'-thio-bis-[(2-trifluoromethyl)benzene-amine]; [0158] 68.
4,4'-thiobis-[(3-trifluoromethyl)benzene amine]; [0159] 69.
4,4'-sulfoxyl-bis-[(2-trifluoromethyl)benzene amine; [0160] 70.
4,4'-sulfoxyl-bis-[(3-trifluoromethyl)benzene amine]; [0161] 71.
4,4'-keto-bis-[(2-trifluoromethyl)benzene amine]; [0162] 72.
9,9-bis(4-aminophenyl)fluorene; [0163] 73.
1,3-diamino-2,4,5,6-tetrafluorobenzene; [0164] 74.
3,3'-bis(trifluoromethyl)benzidine; and mixtures thereof.
[0165] Polyimides of the present disclosure can be made by methods
well known in the art and their preparation need not be discussed
here.
[0166] In some embodiments, the first polyimide layer and the
second polyimide layer each further comprise an amount between (and
optionally including) any two of the following weight percentages
of thermally conductive filler: 5, 10, 15, 20, 25, 30, 35, 40, 45
and 50 weight percent of a thermally conductive filler. The
thermally conductive filler is added to increase the thermal
conductivity of the polyimide substrate thus increasing efficiency
of thermal transfer to the heat sink. The ability to efficiently
dissipate heat from an electronic component, more specifically, a
photovoltaic cell is important as it is known that the performance
of photovoltaic materials decrease with elevated temperatures. In
some embodiments, the thermally conductive filler in the polyimide
substrate is the same as in the adhesive layers. In another
embodiment, the thermally conductive filler may be different from
the thermally conductive filler in the adhesive layers.
[0167] In some embodiments, the thermal conductivity of 25 micron
polyimide films of the present disclosure is at least 0.24 watts/mK
at 25.degree. C. In other embodiments, the thermal conductivity of
the polyimide films of the present disclosure is at least 0.33
watts/mK at 25.degree. C. Xenon nano flash method was used to
determine the thermal conductivity measurements of the present
disclosure. In some embodiments, the thermal conductivity of the
polyimide films of the present disclosure are at least 10% greater
than their unfilled counterparts. In some embodiments, the thermal
conductivity of the polyimide films of the present disclosure are
at least 20% greater than their unfilled counterparts. The thermal
conductivity of the polyimide films of the present disclosure can
be as much as 54% greater, or even more than 108% greater than
their unfilled counterparts. The term "thermal conductivity" herein
denotes a measure of the ability of a material to transfer heat;
given two surfaces on either side of the material with a
temperature difference between them.
[0168] In some embodiments, the polyimide substrate's first
polyimide layer and second polyimide layer each further comprise
from 0, 5, 10, 15 and up to 20 weight percent light absorbing
pigment. In some embodiments, the light absorbing pigment in the
polyimide substrate is the same as the light absorbing pigment in
the adhesive layers. In other embodiments, the light absorbing
pigment in the polyimide substrate is the different than the light
absorbing pigment in the adhesive layers.
[0169] In one embodiment, the polyimide substrate additionally
comprises at least one fluoropolymer adhesive layer having a top
layer and a bottom layer wherein the fluoropolymer adhesive top
layer is attached to the first polyimide layer and the
fluoropolymer adhesive bottom layer is attached to the second
polyimide layer. In some embodiments, the fluoropolymer adhesive
layer is selected from tetrafluoroethylene hexafluoropropylene
copolymer (Teflon.RTM. FEP), tetrafluoroethylene perfluoroalkoxy
copolymer (Teflon.RTM. PFA), tetrafluoroethylene ethylene copolymer
(Tefzel.RTM.), polyvinyl fluoride (Tedlar.RTM.) and mixtures
thereof.
[0170] In some embodiments, the fluoropolymer adhesive layer
additionally comprises a thermally conductive filler. The thermally
conductive filler in the fluoropolymer adhesive layer may be the
same or different from the thermally conductive filler in the first
adhesive layer, second adhesive layer or the polyimide substrate.
In some embodiments, the fluoropolymer adhesive layer thickness is
between (and optionally including) any two of the following
thicknesses: 1, 1.25, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 12.5
microns.
[0171] In some embodiments, the polyimide substrate first polyimide
layer and second polyimide layer comprise two or more additional
polyimide layers. The additional polyimide layers may be the same
or different from the first polyimide layer and the second
polyimide layer. In some embodiments, the additional polyimide
layers contain a thermally conductive filler, a light absorbing
pigment and mixtures thereof. In another embodiment, only some of
the additional polyimide layers contain a thermally conductive
filler, a light absorbing pigment and mixtures thereof. In some
embodiments, the thermally conductive filler and light absorbing
pigment in the additional polyimide layers are the same or
different from the thermally conductive filler and light absorbing
pigment in the first polyimide layer and the second polyimide
layer.
[0172] There is a practical limit to the thickness of the polyimide
substrate. If the polyimide substrate is too thick, thermal
dissipation of the device may be adversely affected. If the
polyimide layers are too thin, dielectric breakdown may occur. The
desired thickness of the polyimide substrate must balance
dielectric properties as well as thermal conductivity. This balance
will depend on the electrical application in which the device of
the present disclosure is used, the voltage applied and the amount
of heat generated. In some embodiments, the polyimide substrate
thickness is between (and optionally including) any two of the
following thicknesses: 8, 12.5, 14, 16, 18, 20, 25, 30, 40, 50, 60,
70, 80, 90, 100, 110, 120, 124 and 150 microns.
[0173] Having thin multiple polyimide layers has an advantage over
a single polyimide layer of the same thickness. Multiple layers
decrease the chance of having pinhole or other defects (foreign
particles, gels, filler or other agglomerates) that could adversely
impact the electrical integrity and electrical breakdown
performance of a dielectric film. The term "pinhole" herein denotes
a small hole that results from non-uniformities in a coating or
preparation process. These defects can be a serious issue
particularly in thin films in terms of electrical performance
unless great care is taken to eliminate them. A single layer film
can be made thicker in an attempt to decrease defects or their
impact on the film's integrity; however, the use of too thick a
film in the present disclosure may adversely impact the thermal
dissipation of the device. A multilayer polyimide substrate having
thin multiple layers would reduce the impact of pinholes and other
defects and also maintain good thermal dissipation. Multiple
polyimide layers can be prepared either by laminating single layers
together with or without a separate adhesive or by coating of a
layer on top of one another or by coextrusion processes to prepare
multilayer films, or by combinations of these. A description of a
coextrusion process for preparing multilayer polyimide films is
provided by EP0659553A1, Sutton et al., and is incorporated herein
by reference. Utilization of multilayers of polyimide helps to
greatly eliminate the occurrence of defects that may span the total
thickness of the dielectric layer because the likelihood of defects
that overlap in each of the individual layers is extremely small
and therefore a defect in any one of the layers is much less likely
to cause an electrical failure through the entire thickness of the
dielectric.
[0174] The polyimide layers of the present disclosure have an
advantage over Tefzel.RTM. (ethylene tetrafluoroethylene copolymer)
layers commonly used in the prior art. Tefzel.RTM. has a dielectric
strength of 4000V/mil. In some embodiments, polyimides of the
present disclosure have a dielectric strength of at least 5400
V/mil. In some embodiments, polyimides of the present disclosure
have a dielectric strength of at least 7400 V/mil. (values are for
1 mil film)
Thermally Conductive Filler
[0175] The term "thermally conductive filler" as used herein refers
to any filler having the ability to conduct heat greater than the
polyimide's ability to conduct heat. The filler can be any shape.
In some embodiments, the thermally conductive filler can have an
average particle size in a range between (and optionally including)
any two of the following sizes: 0.5, 1, 5, 10, 20, 30, 40 50, 60,
70, 80, 90, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500
and 5,000 nanometers, where at least 80, 85, 90, 92, 94, 95, 96,
98, 99 or 100 percent of the dispersed filler is within the above
size range(s). In some embodiments, the thermally conductive
fillers can require milling and filtration to break up or remove
unwanted particle agglomeration which can result in low dielectric
strength.
[0176] In some embodiments, the thermally conductive filler is
selected from a group consisting of aluminum oxide, boron nitride
coated aluminum oxide, granular aluminum oxide, fumed aluminum
oxide, silicon dioxide, granular silicon dioxide, fumed silicon
dioxide, silicon carbide, aluminum nitride, aluminum oxide coated
aluminum nitride, silicon dioxide coated aluminum nitride, titanium
dioxide, boron nitride, cubic boron nitride, hexagonal boron
nitride, diamond, beryllium oxide, talc, zinc oxide and mixtures
thereof.
[0177] There is a practical limit to the amount of thermally
conductive filler that can be added. If the amount of thermally
conductive filler is too high then adhesion, electrical insulating
ability and mechanical properties can be adversely affected.
Light Absorbing Pigment
[0178] The term "light absorbing pigment" as used herein refers any
additive that helps protect a polymer composition from the
long-term degradation effects from light. In some embodiments, the
light absorbing pigment is a UV absorber. In another embodiment,
the light absorbing pigment is a UV stabilizer. In yet another
embodiment, mixtures of UV absorbers and UV stabilizers are used.
In some embodiments, the light absorbing pigment is selected from a
least one UV absorber. In another embodiment, the light absorbing
pigment is selected from at least one UV stabilizer. In yet another
embodiment, mixtures of UV absorbers and UV stabilizers are used.
In some embodiments, the light absorbing pigment is selected from a
group consisting of carbon black, titanium dioxide, benzotriazoles,
benzophenones, hindered amines and mixtures thereof.
[0179] There is a practical limit to the amount of light absorbing
pigment that can be added. If the amount of pigment is too high
then adhesion, electrical insulating ability and mechanical
properties can be adversely affected.
Heat Sink
[0180] The metal heat sink absorbs and dissipates thermal energy or
heat. Heat sinks are used in a wide range of applications wherever
efficient heat dissipation is required. Heat sinks function by
efficiently transferring thermal energy from an object at a higher
temperature to a second object, surrounding air or water, at a
lower temperature with a much greater heat capacity. For purposes
of this disclosure, the heat sink transfers heat or thermal energy
from an electrical component. Efficient function of a heat sink
relies on rapid transfer of thermal energy. The heat sinks are
typically composed of thermally conducting materials such as
aluminum, anodized aluminum or thermally conductive polymers. Their
construction can be as simple as a metal plate to a metal device
with many fins. The high thermal conductivity of the metal combined
with its large surface area result in the rapid transfer of thermal
energy to the surrounding, cooler, air. This cools the heat sink
and whatever it is in direct thermal contact with.
[0181] As used herein, the terms "comprises," "comprising,"
"includes," "including," "has," "having" or any other variation
thereof, are intended to cover a non-exclusive inclusion. For
example, a method, process, article, or apparatus that comprises a
list of elements is not necessarily limited only those elements but
may include other elements not expressly listed or inherent to such
method, process, article, or apparatus. Further, unless expressly
stated to the contrary, "or" refers to an inclusive or and not to
an exclusive or. For example, a condition A or B is satisfied by
any one of the following: A is true (or present) and B is false (or
not present), A is false (or not present) and B is true (or
present), and both A and B are true (or present).
[0182] Also, use of the "a" or "an" are employed to describe
elements and components of the disclosure. This is done merely for
convenience and to give a general sense of the disclosure. This
description should be read to include one or at least one and the
singular also includes the plural unless it is obvious that it is
meant otherwise.
EXAMPLES
[0183] The present disclosure will be further described in the
following examples. Examples are not intended to limit the scope of
this disclosure. [0184] Kapton.RTM. 200 CR A multilayer aromatic
polyimide film containing aluminum oxide, 50 microns (2 mil) thick,
available from E.I. du Pont de Nemours and Company, Wilmington,
Del. [0185] Kapton.RTM. 100 MT A multilayer aromatic polyimide film
containing aluminum oxide, 25 microns (1 mil) thick, available from
E.I. du Pont de Nemours and Company, Wilmington, Del. [0186]
BixCure Ethylene vinyl acetate available from Bixby International
Corporation. Newburyport, Mass. [0187] Elvaloy 4170 Ethylene
n-butylacrylate glycidyl methacrylate (EnBAGMA) terpolymer
available from E.I. du Pont de Nemours and Company, Wilmington,
Del. [0188] Nucrel 0910 Ethylene methacrylic acid (EMAA) copolymer,
available from E.I. du Pont de Nemours and Company, Wilmington,
Del. [0189] Elvax 3185 Ethylene vinyl acetate available from E.I.
du Pont de Nemours and Company, Wilmington, Del. [0190] Elvaloy AC
1330 Ethylene methacrylate (EMA) copolymer available from E.I. du
Pont de Nemours and Company, Wilmington, Del.
Example 1
[0191] Example 1 illustrates the use of a Kapton.RTM. 200 CR
polyimide film and a formulated ethylene vinyl acetate (EVA)
copolymer adhesive. A 50 micron (2 mil) Kapton.RTM. 200 CR film is
coated with an aqueous dispersion of tetrafluoroethylene
hexafluoropropylene which is subsequently dried and cured to a
fluoropolymer film of about 2.5 micron (0.1 mil) thickness. Two of
these fluoropolymer coated polyimide films are subsequently
laminated together with the fluoropolymer layers facing each other
to yield a multilayer film of about 105 microns (4.2 mil) total
thickness. Onto this composite film, BixCure, a formulated ethylene
vinyl acetate (EVA) copolymer is extrusion coated to a thickness of
about 25 microns (1 mil) to 75 microns (3 mil). Bonding results
between the adhesive and the polyimide film are shown in table 1.
This adhesive coated polyimide film was subsequently laminated to
an aluminum plate and the EVA copolymer layer cured to yield an
electrically insulating, thermally conductive device for which the
bonding results of the composite film to the aluminum plate are
shown in table 1. Results for subjecting this device to water
soaking at ambient temperature for greater than 12 days is shown in
table 2. In combination with the aluminum heat sink, the Kapton CR
based composite film is expected to provide excellent electrical
insulation performance and very high dielectric breakdown strength
while still allowing adequate thermal dissipation performance.
Example 2
[0192] Example 2 illustrates the use of a Kapton.RTM. 200 CR
polyimide film and Elvaloy 4170 adhesive.
[0193] The sample is prepared in a similar manner to example 1.
[0194] Results are shown in tables 1 and 2.
Example 3
[0195] Example 3 illustrates the use of a Kapton.RTM. 200 CR
polyimide film and Nucrel 0910 adhesive.
[0196] The sample is prepared in a similar manner to example 1.
[0197] Results are shown in tables 1 and 2.
Example 4
[0198] Example 4 illustrates the use of a Kapton.RTM. 100 MT
polyimide film and BixCure. BixCure is extrusion coated onto
Kapton.RTM. 100 MT polyimide film to produce a polyimide composite
film. The Kapton MT would be expected to provide higher thermal
dissipation performance vs. the equivalent construction based on
Kapton CR, while still providing adequate electrical insulation
performance.
[0199] The sample is prepared in a similar manner to example 1.
[0200] Results are shown in tables 1 and 2.
Example 5
[0201] Example 5 illustrates the use of a Kapton.RTM. 100 MT
polyimide film and Elvaloy 4170 adhesive.
[0202] The sample is prepared in a similar manner to example 1.
[0203] Results are shown in tables 1 and 2.
Example 6
[0204] Example 6 illustrates the use of a Kapton.RTM. 100 MT
polyimide film and Nucrel 0910 adhesive.
[0205] The sample is prepared in a similar manner to example 1.
[0206] Results are shown in tables 1 and 2.
Comparative Example 1
[0207] Comparative Example 1 illustrates the use of a Kapton.RTM.
200 CR polyimide film and Elvax 3185 copolymer adhesive.
[0208] The sample is prepared in a similar manner to example 1.
[0209] Results are shown in tables 1 and 2.
Comparative Example 2
[0210] Comparative Example 2 illustrates the use of a Kapton.RTM.
100 MT polyimide film and Elvax 3185 copolymer adhesive.
[0211] The sample is prepared in a similar manner to example 1.
[0212] Results are shown in tables 1 and 2.
Comparative Example 3
[0213] Comparative Example 3 illustrates the use of a Kapton.RTM.
200 CR polyimide film and Elvaloy AC 1330copolymer adhesive.
[0214] The sample is prepared in a similar manner to example 1.
[0215] Results are shown in tables 1 and 2.
Comparative Example 4
[0216] Comparative Example 4 illustrates the use of a Kapton.RTM.
100 MT polyimide film and Elvaloy AC 1330 copolymer adhesive. The
sample is prepared in a similar manner to example 1.
[0217] Results are shown in tables 1 and 2.
[0218] The test results for adhesion for initial adhesion and
adhesion after soaking are shown below.
[0219] Excellent means could not be separated without tearing.
[0220] Peelable means could be peeled but good adhesion.
[0221] Poor means unacceptable adhesion.
TABLE-US-00001 TABLE 1 Initial Adhesion Kapton .RTM. Kapton .RTM.
Aluminum Photovoltaic 200 CR 100 MT sheeting cell Example 1
excellent excellent excellent BixCure Example 2 excellent excellent
excellent Elvaloy 4170 Example 3 excellent excellent excellent
Nucrel 0910 Example 4 excellent excellent excellent BixCure Example
5 excellent excellent excellent Elvaloy 4170 Example 6 excellent
excellent excellent Nucrel 0910 Comparative Ex. 1 excellent
peelable Elvax 3185 Comparative Ex. 2 excellent peelable Elvax 3185
Comparative Ex. 3 Excellent peelable Elvaloy AC 1330 Comparative
Ex. 4 excellent peelable Elvaloy AC 1330
TABLE-US-00002 TABLE 2 Adhesion after soaking at ambient
temperature for greater than 12 days Kapton .RTM. Kapton .RTM.
Aluminum Photovoltaic 200 CR 100 MT sheeting cell Example 1
excellent peelable excellent BixCure Example 2 excellent excellent
excellent Elvaloy 4170 Example 3 excellent excellent excellent
Nucrel 0910 Example 4 excellent peelable excellent BixCure Example
5 excellent excellent excellent Elvaloy 4170 Example 6 excellent
excellent excellent Nucrel 0910 Comparative Ex. 1 excellent poor
Elvax 3185 Comparative Ex. 2 excellent poor Elvax 3185 Comparative
Ex. 3 excellent poor Elvaloy AC 1330 Comparative Ex. 4 excellent
poor Elvaloy AC 1330
[0222] Note that not all of the activities described above in the
general description or the examples are required, that a portion of
a specific activity may not be required, and that further
activities may be performed in addition to those described. Still
further, the order in which each of the activities are listed are
not necessarily the order in which they are performed. After
reading this specification, skilled artisans will be capable of
determining what activities can be used for their specific needs or
desires.
[0223] In the foregoing specification, the invention has been
described with reference to specific embodiments. However, one of
ordinary skill in the art appreciates that various modifications
and changes can be made without departing from the scope of the
invention as set forth in the claims below. Accordingly, the
specification and figures are to be regarded in an illustrative
rather than a restrictive sense and all such modifications are
intended to be included within the scope of the invention.
[0224] Benefits, other advantages, and solutions to problems have
been described above with regard to specific embodiments. However,
the benefits, advantages, solutions to problems, and any element(s)
that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical,
required, or essential feature or element of any or all the
claims.
[0225] When an amount, concentration, or other value or parameter
is given as either a range, preferred range or a list of upper
values and lower values, this is to be understood as specifically
disclosing all ranges formed from any pair of any upper range limit
or preferred value and any lower range limit or preferred value,
regardless of whether ranges are separately disclosed. Where a
range of numerical values is recited herein, unless otherwise
stated, the range is intended to include the endpoints thereof, and
all integers and fractions within the range. It is not intended
that the scope of the invention be limited to the specific values
recited when defining a range.
* * * * *