U.S. patent application number 09/879327 was filed with the patent office on 2002-01-17 for process of injection molding highly conductive molding compounds and an apparatus for this process.
Invention is credited to Butler, Kurt I., Thomas, Daniel G..
Application Number | 20020005508 09/879327 |
Document ID | / |
Family ID | 27395643 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020005508 |
Kind Code |
A1 |
Butler, Kurt I. ; et
al. |
January 17, 2002 |
Process of injection molding highly conductive molding compounds
and an apparatus for this process
Abstract
A technique and apparatus are disclosed for injection molding
highly filled conductive resin compositions. These compositions
include one or more of unsaturated polyester and vinyl ester resin;
a copolymer having a terminal ethylene group; and at least about 50
weight percent of an inorganic particulate conductive filler, an
initiator, and a rheological modifier to prevent phase separation
between said resin and said conductive filler during molding. The
method of the present invention allows these compositions to be
molded into highly intricate and thin electrically and thermally
conductive specimens without significant post process machining.
The method involves the use of an injection molding apparatus that
has a hopper with an auger having a vertical component in its
positioning to feed into the feed throat of an injection molding
machine which has a phenolic screw that has been modified to have a
constant inner diameter and a constant flight depth.
Inventors: |
Butler, Kurt I.;
(Kingsville, OH) ; Thomas, Daniel G.; (Conneaut,
OH) |
Correspondence
Address: |
HUDAK & SHUNK CO., L.P.A.
Suite 808
7 West Bowery Street
Akron
OH
44308-1133
US
|
Family ID: |
27395643 |
Appl. No.: |
09/879327 |
Filed: |
June 12, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09879327 |
Jun 12, 2001 |
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09849629 |
May 4, 2001 |
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09849629 |
May 4, 2001 |
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09526641 |
Mar 16, 2000 |
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6251308 |
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60125138 |
Mar 19, 1999 |
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60211582 |
Jun 15, 2000 |
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Current U.S.
Class: |
252/500 |
Current CPC
Class: |
C08F 283/01 20130101;
Y02E 60/50 20130101; C08L 63/00 20130101; H01M 8/0221 20130101;
H01M 4/668 20130101; H01M 8/247 20130101; B29C 45/0001 20130101;
C08F 290/14 20130101; C08F 290/06 20130101; B29C 45/0013 20130101;
H01M 8/0226 20130101; C08K 3/04 20130101; B29L 2031/3468 20130101;
B29C 45/18 20130101; H01M 8/0213 20130101; Y02E 60/10 20130101;
H01M 8/0263 20130101 |
Class at
Publication: |
252/500 |
International
Class: |
H01B 001/06 |
Claims
What is claimed is:
1. A process for molding a product from a composition in an
injection molding apparatus having a feed throat which feeds a shot
of composition into a mold, said composition comprising; a) an
unsaturated prepolymer resin which comprises one or more of
unsaturated polyester and vinyl ester resin; b) an unsaturated
material copolymerizable with said resin and including a terminal
ethylene group; c) an inorganic particulate conductive filler in an
amount sufficient to provide a bulk conductivity of at least 40
S/cm to the resulting product; and d) an initiator to initiate said
copolymerization; and wherein the composition is ported directly
into the feed throat by an auger which has a vertical component to
its positioning relative to the plane of the injection molding
apparatus, and said shot is fed into the mold by a phenolic screw
within the feed throat.
2. A process as set forth in claim 1 wherein the amount of said
conductive filler is at least 50 weight percent.
3. A process as set forth in claim 2 wherein the filler is a
graphite filler and the amount of said conductive filler is at
least 60 weight percent.
4. A process as set forth in claim 1 wherein the composition
further comprises an effective amount of a rheological modifier to
prevent phase separation between said resin and said conductive
filler during molding, said rheological modifier being one or more
compositions selected from the group consisting of Group II oxides
and hydroxides, carbodiamides, aziridines, polyisocyanates,
polytetrafluorethylene, perfluoropolyether, polyethylene and fumed
silica.
5. A process as set forth in claim 4 wherein said composition is
molded into a product which has an intricate pattern molded therein
and has a thickness from about 0.050 to about 0.200 inches and a
bulk conductivity of at least about 50 S/cm.
6. A process as set forth in claim 5 wherein said product is an
electrochemical cell flow field plate.
7. A process as set forth in claim 6 wherein said conductive filler
comprises a crystalline graphite particle and, and said unsaturated
prepolymer resin is one or more resins selected from the group
consisting of epoxy vinyl resin, bisphenol fumarate resin, modified
bisphenol fumarate polyester resin, unsaturated polyester resin,
urethane modified vinyl ester resin, bisphenol-epoxy vinylester
resin, elastomer-modified vinyl ester resin, epoxy novolac vinyl
ester resin and unsaturated isocyanurate vinyl ester resin.
7. A process as set forth in claim 7 wherein said auger is at an
angle of from about 30 to about 60 from the horizontal plane of the
injection molding apparatus.
8. A process as set forth in claim 8 wherein the auger is at an
angle of from about 40 to about 50 degrees from the horizontal
plane of the injection molding apparatus.
9. A process as set for the in claim I wherein the auger is
substantially vertical and is feed by a second auger which is
substantially horizontal relative to the plane of the injection
molding apparatus.
10. A process as set forth in claim 9 wherein the phenolic screw
has a tip which is modified to a constant inner diameter and a
constant flight depth.
11. A process as set forth in claim 10 wherein the auger has been
modified to match and blend into the feed throat area to eliminate
any dead spots.
12. A process for molding a product from composition in an
injection molding apparatus having a feed throat which feeds a shot
of composition into a mold, said composition comprising; a) an
unsaturated prepolymer resin which comprises one or more of
unsaturated polyester and vinyl ester resin; b) an unsaturated
material copolymerizable with said resin and including a terminal
ethylene group; c) an inorganic particulate conductive filler in an
amount of at least about 50 weight percent of the weight of the
composition; d) an initiator to initiate said copolymerization; and
e) an effective amount of a rheological modifier to prevent phase
separation between said resin and said conductive filler during
molding, said rheological modifier being one or more compositions
selected from the group consisting of Group II oxides and
hydroxides, carbodiamides, aziridines, polyisocyanates,
polytetrafluorethylene, perfluoropolyether, polyethylene and fumed
silica; and wherein the composition is ported directly into the
feed throat by an auger which has a vertical component to its
positioning relative to the plane of the injection molding
apparatus, and said shot is fed into the mold by a phenolic screw
within the feed throat.
13. A process as set forth in claim 12 wherein the filler is a
graphite filler and the amount of said conductive filler is at
least 60 weight percent.
14. A process as set forth in claim 13 wherein said composition is
molded into a product which has an intricate pattern molded therein
and has a thickness from about 0.050 to about 0.200 inches and a
bulk conductivity of at least about 50 S/cm.
15. A process as set forth in claim 14 wherein said product is an
electrochemical cell flow field plate.
16. A process as set forth in claim 15 wherein said conductive
filler comprises a crystalline graphite particle and, and said
unsaturated prepolymer resin is one or more resins selected from
the group consisting of epoxy vinyl resin, bisphenol fumarate
resin, modified bisphenol fumarate polyester resin, unsaturated
polyester resin, urethane modified vinyl ester resin,
bisphenol-epoxy vinyl ester resin, elastomer-modified vinyl ester
resin, epoxy novolac vinyl ester resin and unsaturated isocyanurate
vinyl ester resin.
17. A process as set forth in claim 12 wherein said auger is at an
angle of from about 30 to about 60 from the horizontal plane of the
injection molding apparatus.
18. A process as set forth in claim 17 wherein the auger is at an
angle of from about 40 to about 50 degrees from the horizontal
plane of the injection molding apparatus.
19. A process as set for the in claim 12 wherein the auger is
substantially vertical and is feed by a second auger which is
substantially horizontal relative to the plane of the injection
molding apparatus.
20. A process as set forth in claim 12 wherein the phenolic screw
has a tip which is modified to a constant inner diameter and a
constant flight depth.
21. A process as set forth in claim 20 wherein the auger has been
modified to match and blend into the feed throat area to eliminate
any dead spots.
22. An injection molding apparatus for molding a product from
composition having at least about 50 weight percent of an inorganic
particulate filler comprising; a hopper having an auger with a
vertical component to its positioning relative to the horizontal
plane of the injection molding apparatus; and an injection molding
machine with a feed throat which feeds the composition into a
phenolic screw which conveys the composition into a mold cavity
wherein said auger has been modified to match and blend into the
feed throat to eliminate any dead spots and the phenolic screw has
a tip with a constant inner diameter and a constant flight
depth.
23. An injection molding apparatus as set forth in claim 22 wherein
the auger is at an angle of from about 40 to about 50 degrees from
the horizontal plane of the injection molding apparatus.
24. A process as set for the in claim 22 wherein the auger is
substantially vertical and is feed by a second auger which is
substantially horizontal relative to the plane of the injection
molding apparatus.
Description
CROSS REFERENCE
[0001] THIS PATENT APPLICATION IS A CONTINUATION-IN-PART OF U.S.
patent application Ser. No. 09/849,629 FILED May 4, 2001 WHICH IS A
CONTINUATION-IN-PART OF U.S. application Ser. No. 09/526,641 FILED
Mar. 16, 2000 WHICH IS BASED ON U.S. PROVISIONAL APPLICATION Ser.
No. 601125,138 FILED Mar. 18, 1999, AND ALSO CLAIMS PRIORITY FROM
U.S. PROVISIONAL APPLICATION Ser. No. 60/211,582 FILED Jun. 15,
2000.
FIELD OF INVENTION
[0002] The field of invention is molding processes for highly
conductive compositions that are particularly useful for
intricately molded conductive products, such as for example for
fuel cell plates. These processes involve novel injection, and
injection/compression molding processes.
[0003] These molding compositions can be formed into high
definition complex configurations, including configurations, which
are particularly suitable for injections molding techniques. For
example, they can be molded into thin plate-like specimens (e.g. 60
to 200 thousandths of an inch) having an intricately patterned
network of very narrow, relatively smooth, flow passages. Moreover
in accordance with the present invention, these labyrinthine plates
can be made substantially exclusively by molding, meaning that the
need for complex and expensive machining processes is virtually
eliminated. Such specimens are used as electrochemical cell bipolar
plates. These plates desirably have a bulk conductivity of at least
40, 50, 60, 70, 80, 90 or even 96 S/cm. They also have desirable
surface characteristics; heat, temperature, chemical and shrink
resistance; strength; and cost.
BACKGROUND OF THE INVENTION
[0004] Conductive polymers have applications in providing
alternatives to traditional conductive materials, which often
involve greater labor expenses to manufacture into complex parts.
In particular, in instances where the demand justifies significant
volumes of a product, polymer-molding expenses may prove far more
cost effective than comparable machining expenses for other
materials. However in the past, it has proved difficult to achieve
both a high level of conductivity and desirable molding
characteristics. Generally, high-level weight percentages of an
appropriate filler in a polymeric matrix are necessary to achieve
satisfactory levels of conductivity. However, these high load
levels lead to problems with the strength, durability, and
moldability of the resulting composition One area in particular
where it would be beneficial to solve the previously mentioned
strength, durability, and molding issues is for application in fuel
cells. Electrochemical fuel cells have great appeal as a
potentially limitless energy source that is clean and
environmentally friendly. These fuel cells can, in addition, be
constructed at an appropriate scale for small-scale energy
consumption, such as household use, or for industrial scale use,
and even for commercial power generation. They have portable
applications to power small appliances (such as computers or
camping equipment), or automobiles and other forms of
transportation. Although these different applications involve
differences in size, the fundamental construction remains the same
for generation of power varying from less than one to a few
thousand kilowatts.
[0005] Basically, a fuel cell is a galvanic cell in which the
chemical energy of a fuel is converted directly into electrical
energy by means of an electrochemical process. The fundamental
components of the fuel cell are an electrode comprising an anode
and a cathode, eletrocatalysts, and an electrolyte. Work has been
done in perfecting both liquid and solid electrolyte fuel cells and
the present invention may find use in both types of fuel cells.
[0006] Solid electrolytes include polymeric membranes, which act as
proton exchange membranes typically fueled by hydrogen. These
membranes usually comprise a perfluorinated sulphonic acid polymer
membrane sandwiched between two catalyzed electrodes that may
utilize platinum supported on carbon as an electrocatalyst.
Hydrogen fuel cells form a reaction chamber, which consumes
hydrogen at the anode. At the cathode, oxygen reacts with protons
and electrons at the electrocatalytic sites yielding water as the
reaction product. A three-phase interface is formed in the region
of the electrode and a delicate balance must be maintained between
the electrode, the electrolyte, and the gaseous phases.
[0007] Systems involving the use of other electrolytes have been
also been studied. These would include alkaline fuel cells,
phosphoric acid fuel cell, molten carbonate fuel cells, and solid
oxide fuel cells. However, the principles are similar, as are some
of the issues in perfecting these products.
[0008] A fuel cell reactor may comprise a single-cell or a
multi-cell stack. In any case, the cell includes at least two
highly conductive flow field plates that serve multiple functions.
These plates may function as current collectors that provide
electrical continuity between the fuel cell voltage terminals and
electrodes. They also provide mechanical support (for example for
the membrane/electrode assembly). In addition, these plates act to
transport reactants to the electrodes and are essential to
establishing the previously mentioned delicate phase balance.
[0009] Typically, the fuel cell plates are thin relatively flat
plate members that include a highly complex network of
interconnecting channels that form the flow field area of the
plate. The configuration of these channels is highly developed in
order to maintain the proper flow of reactants and to avoid
channeling or the formation of stagnant areas, which results in
poor fuel cell performance. It is critical that the flow of the
reactants is properly managed, and that the electrocatalysts are
continuously supplied with precisely the appropriate balance of
reactants. Thus, it is essential for the plates to define and
maintain clear passages within the highly engineered flow
labyrinth. Moreover, in order to assure a satisfactory life, the
plates must be able to resist surface corrosion under a variety of
conditions. For example, fuel cells may be placed outside and
subject to ambient weather. Thus, the cells must be resistant to
stress cracking and corrosion at temperature ranging from -40 to
200 degrees Fahrenheit. Further, since the conditions within the
cell are corrosive, the cells must also be resistant to chemical
attack at these temperatures from various corrosive substances. For
example, the plates may be subjected to de-ionized water, methanol,
formic acid, formaldehyde, heavy naptha, hydrofluoric acid,
tertafluoroethylene, and hexafluoropropylene depending on the fuel
cell type. Moreover, the conditions within the fuel cell may lead
to elevated temperatures, i.e. from 150 to 200 degrees Fahrenheit,
as well as elevated pressures, i.e. from ambient to 30 p.s.i.
Corrosive decomposition needs to be avoided since it almost
certainly would cause a system failure by changing the flow
patterns within the fuel cell.
[0010] Past attempts at solving the various requirements for fuel
cell plates have included the use of metal and machined graphite
plates. The use of metal plates result in higher weight per cell,
higher machining costs and possibly corrosion problems. Machined
graphite plates solve the weight and corrosion problems but involve
high machining cost and result in fragile products, especially when
prepared as very thin plates. Some use of graphite/poly(vinylidene
fluoride) plates has been made but these have been characterized as
being expensive and brittle and having long cycle times.
[0011] U.S. Pat. No. 4,197,178 is incorporated herein for its
teaching of the working and compositions of electrochemical cells.
U.S. Pat. No. 4,301,222 is incorporated herein for its teachings on
graphite-based separators for electrochemical cells.
SUMMARY OF THE INVENTION
[0012] In the past, known conventional bulk molding compounds have
been modified to be conductive by the addition of large amounts of
conductive filler, such as graphite. During molding it was observed
that the liquid resin phase separated from the filler and was
exuded from the molding. Further, it was observed that this
occurrence tended to cause cracking in molded specimens that were
thin. Moreover, bulk conductivity measurements at different
locations within the specimen were inconsistent. In accordance with
the present invention, it was discovered that compositions could be
formulated which solved the foregoing issues. In particular, the
formulations involve the use of a resin matrix with high loadings
of a conductive filler; various additional additives, such as
initiators, mold-release agents, and carbon black; and optionally
one or more Theological agents selected from the group comprising
group 11 oxides, alkaline earth oxides, carbodiamides,
polyisocynates, polyethylene and polytetraethylene fluoethylene.
One possible explanation for the mechanism by which the molding
agents work, is that they act to build the apparent molecular
weight of the prepolymer (e.g. vinyl ester resin or unsaturated
polyester resin). Alternatively, these agents may promote flow such
as by reducing shear during molding. The use of these Theological
agents eliminates phase separation, as well as cracking and
inconsistent conductivity measurements. It is anticipated that
these problems are a result of the complex configuration of the
specimens being molded along with the very high concentrations of
conductive filler.
[0013] In addition to solving molding and cracking problems it is
anticipated that other properties such as the coefficient of
thermal expansion, electrical and thermal conductivity, shrink
resistance and mechanical properties may be more uniform and/or
otherwise improved as a result of the use of the present invention.
In addition to the foregoing improvements it was found that a resin
composition of the invention demonstrated a higher glass transition
temperature and resulted in an improvement in the hot strength of
the molded part. Further improvements are also possible by
optimizing both gel time and cure time for the prepolymer by
controlling initiator type and amount and inhibitor type and
amount. Additionally, the compositions can include the use of a low
shrink additive is added to the composition which acts to help
perfect the surface characteristics of the molded plate made in
accordance with the invention. These additives are generally used
in the range of 10 to 50 weight percent based on the total weight
of the additive and the resin system, i.e. the resin and any
monomers. For the purpose of this invention, the term "low shrink
additive" is used but may encompass additives which are also termed
"low profile additives" and help to reduce the roughness of the
surface. Resins may have a tendency to shrink during cure which
results in surface defects such as sink marks and microscopic
irregularities. Other problems include internal voids and cracks,
as well as warpage and inability to mold to close tolerances. For
molded fuel cell plates, these imperfections inhibit the ability of
the resultant product to contact the proton exchange membrane. The
"low profile additives" of the present invention help to compensate
for shrinkage and improve the surface smoothness. Further,
eliminating the shrink problems results in better stacking of the
plates and a better overall fuel cell.
[0014] The foregoing improvements in specimens molded from these
compositions enable the low cost mass production of bipolar plates
as an additional embodiment of the invention. These could be used
for portable fuel cells, as well as stationary power units.
[0015] In accordance with the invention, the following compositions
can be used in a new molding process to accomplish injection
molding. In particular, the process of the present invention
involves using a double auger to convey the highly loaded molding
compositions of the present invention to the feed throat of an
injection molding apparatus. Alternatively, it has also been found
that a single auger, such as is found in an injection molding
machine sold by Krauss Maffei with an AZ100 stuffing unit and a
60mm screw and barrel for thermoset BMC, can be used where the
auger is disposed at a angle of between about 30 and 60 degrees to
the horizontal plane of the feed throat. More particularly, the
angle is about 45 degrees plus or minus 5 degrees. These processes
together contrasts to the traditional process using a hydraulic ram
to port the molding composition to the feed throat. However, the
traditional molding methods and equipment would fail with
potentially catastrophic results when the composition would pack
out during the molding process. As compared to these traditional
methods, it is preferred that a double auger system with a first
and larger horizontally oriented screw, which feeds the smaller
vertical type auger feeding into the feed throat. Further, the
process involves some zoned temperature gradients with a first and
second zone in the first screw barrel having a temperature of from
about 70 to about 125 degrees F, and more particularly about 70 to
about 100 degrees F. A third zone is located at the mold. This zone
is maintained at about 275 to about 325 (i.e. 300 F) which is the
temperature at which cure is initiated for most of the compositions
in accordance with the invention. It is preferable to avoid
temperature variations at the mold level. At normal cure rates, the
mold time is typically around 10 to 600 seconds, or more usually 30
to 300 seconds or around one or two minutes. The process can be
practiced for single or double gate cavity tools, or even for
injection/compression processes in which the mold is slightly
opened during fill and the mold is shut to compress the shot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an illustration of a fuel cell assembly utilizing
a bipolar cell plate;
[0017] FIG. 2 is an illustration of a bipolar fuel cell plate that
can be made in accordance with the present invention;
[0018] FIG. 3 is an illustration of a process failure for
composition in accordance with the present invention molded using
the convention hydraulic ram injection molding process;
[0019] FIG. 4 is an illustration of the mold plug shown in FIG.
3;
[0020] FIG. 5 is a schematic illustration of the molding equipment
of the present invention; and
[0021] FIG. 6 is a schematic illustration of a further embodiment
of the molding equipment of the present invention
DETAILED DESCRIPTION OF THE INVENTION
[0022] The invention relates to improvements in processes and
equipment for molding highly conductive molding compositions. In
particular, the compositions can be used in injection molding
processes, and in injection/compression molding processes. These
processes are cost effective because they eliminate labor intensive
machining, and because of repeatability with respect to shot to
shot. The processes further have better ability to control shot to
shot cross parting line thickness. Further these molding processes
enable the production of thin and intricate specimens that have
high concentrations of conductive filler.
[0023] Sheet molding and bulk molding compositions are described in
U.S. Pat. Nos. 5,998,510; 5,342,554; 5,854,317; 5,744,816; and
5,268,400; all of which are hereby incorporated by reference for
their teachings on the various modifications to molding
compositions that are known to the art.
[0024] One component of a molding resin composition is a
crosslinkable prepolymer such as an unsaturated polyester resin or
vinyl ester resin. Desirably the prepolymer has a relatively low
molecular weight such as from about 200 to about 5000 (weight
average). They are described in detail with examples in the above
patents incorporated by reference. The polyester resins are the
condensation product derived from the condensation of unsaturated
polybasic acids and/or anhydrides with polyols such as dihydroxy or
trihydroxy compounds. Desirably, these polyester resins are the
esterification reaction product of diacids, or anhydrides of
diacids, generally having from about 3 to about 12, or more
preferably from about 4 to about 8 carbon atoms, with a polyol or a
cyclic ether having from about 2 to about 12, or more preferably
from about 2 to about 6 carbon atoms.
[0025] In general, the vinyl ester resins that can be used are the
reaction products of epoxy resins and a monofunctional ethlenically
unsaturated carboxylic acid. More specifically, these vinyl ester
resins are the reaction product of an epoxy terminated oligomer,
for example, an epoxy functionalized bisphenol A with an acrylic
acid, or methacrylic acid forming acrylic terminal groups on the
oligomer. The vinyl esters have predominantly terminal unsaturation
while the unsaturated polyesters have predominantly internal
unsaturation.
[0026] Another component of the molding composition is one or more
unsaturated monomers that are copolymerizable with the resin.
Desirably, this component is cabable of dissolving the resin
component at room temperature. Thus, in one embodiment the resin is
dissolved in the monomeric component prior to being combined with
the remaining components. Examples of suitable monomers are
styrene, alpha-methyl styrene, chloro-styrene, vinyl toluene,
divinyl benzene, diallylphthalate, methyl methacrylate, and mixture
of these, with preferred monomers being styrene and methyl
methacrylate. The ratio of monomer(s) to resin is desirably from
about 40:60 to about 75:25 and preferably from about 40:60 to about
65:35 by weight.
[0027] Another component to the molding composition is fillers. In
accordance with the invention the predominant filler is a
conductive filler in order to impart electrical conductivity of the
final molded product. A preferred filler is graphite particles, in
particular, a synthetic crystalline graphite particle, such as
currently supplied by Asbury Graphite in Asbury, New Jersey under
the designation Asbury 4012. This graphite is characterized as
having less than 10% particles greater than 150 microns and less
than 10% smaller than 44 microns in diameter. Other graphite
fillers include: Ashbury A99, Ashbury 3243, Ashbury modified 4012,
Ashbury 3285, Ashbury 230U; TimrexR KS 75 and 150, and TimrexR KC
44, all sold by TIMCAL of Westlake, Ohio; and Calgraph Sold by SGL
Technic Inc of Valencia, California. This filler is used at a
loading of at least 50% by weight. Other conductive fillers such as
other forms of graphite (including graphite pitch-based fibers),
metal particles, or metal coat particles may be used in conjunction
with the graphite filler, or even alone. Desirably conductive
fillers are at least about 50,about 60, or about 65 weight percent
of the molding composition. More desirably the filler is more than
about 70 or 75 percent to about 80 weight percent of the molding
composition. Alternatively this amount can be expressed as at least
about 250phr, more preferably at least about 275, or even 300 phr.
Alternatively stated the conductive fillers are present in an
effective amount to result in a bulk conductivity of at least about
40, about 50, about 60, about 70, about 80, about 85, about 90 or
about 96 S/cm when measured in accordance with ASTM Test Standard
No. F1529-97 for a molded article having a thickness from about
0.060 to about 0.200 inches. Current technology in fuel cell plates
uses a bulk conductivity of at least about 55 S/cm, and preferably
at least about 70.
[0028] An initiator is another component of the molding
composition. The initiator initiates the copolymerization of the
resin and the monomer(s). Initiators include any free radical
initiator capable of forming radicals in the correct concentration
under the molding conditions. They may include peroxides,
hydroperoxides, redox systems, diazo compounds, persulfates,
perbenzoates etc. The initiators are typically used in amounts of
about 0.05 to about 5 weight percent, and more preferably about 0.1
to about 2 weight percent. Alternatively, these amount can be
expressed in parts per hundred parts by weight of resin, i.e. from
about 0.5 to about 4.0 phr, preferably from about 0.7 to about 3.0
phr, and most preferably from about 0.8 to about 2.25 phr.
Alternatively high temperature initiators such as Di-cup, e.g.
dicumyl peroxide can be used for molding applications where higher
iniation temperatures are desirable. The inclusion of 0.5 to 10phr,
preferably about 1 to 8 phr, of a mold release agent, such as
calcium stearate, zinc stearate, or the like may also be of
advantage to achieving without machining the highly complex molded
part of the present invention.
[0029] Another optional component to the improved molding
composition is a rheological modifier, which may act to increase
the molecular weight such as by chain extension of the resin
prepolymer. Suitable modifiers include Group II oxides and
hydroxides, such as calcium or magnesium oxide; carbodiamides;
aziridines; and polyisocyanates. It is believed that the foregoing
modifiers act chemically by co-reacting into the polymer backbone
at carboxy or hydroxy sites. Other suitable modifiers include
polytetrafluorethylene (PTFE); perfluoropolyether (PFPE), and
polyethylene. These modifiers may act to reduce shear and thus
promote flow in the composition during molding. Fumed silica is an
example of a substance, which may act mechanically to increase
molding viscosity and therefore be a suitable Theological modifier
for this invention. Combinations of two or more rheological
modifiers may be desirable for optimum properties. In this
application they are used to modify the resin structure to prevent
phase separation of the resin from the conductive filler (in
particular in view of the high loadings of the conductive filler,
i.e. over 50% or even 65% by weight or more of graphite) The
modifiers are further used in general to enable the achievement of
a high definition conductive polymeric fuel cell plate.
[0030] Desirably the rheological modifiers are used in an effective
amount to prevent phase separation during molding. For the purpose
of this application molding will desirably be at pressures from
about 400 to about 5000 psi, and preferably from about 2000 to
about 3500 psi, and most preferably from about 2500 to about 3000
psi. Desirable amounts of group 11 oxides (including group II
hydroxides and mixtures of these compounds) is from about 0.1 to
about 1 or about 2 weight percent, more desirably from about 0.2 or
about 0.3 to about 0.7 or about 0.8 weight percent. This can also
be expressed as from about 0.5 to about 4.0 phr, preferably from
about 1.0 to about 3.0 phr, and most preferably from about 1.5 to
about 2.5 phr. Specific preferred compounds include magnesium
oxide, or magnesium hydroxide or calcium oxide. Examples of a
suitable magnesium oxide additives is 99% pure magnesium oxide sold
under the tradename "Elastomag" from Morton Thiokol, Inc. in
Danvers, Mass. Other examples include a magnesium oxide dispersion
sold under the tradename "pg-9033" by plasticolors, and a magnesium
hydroxide dispersion also sold by plasticolors under the tradename
"pg-91146". Another suitable magnesium hydroxide is Barcroft, which
is a powdered version. Examples of aziridine compounds include
polyfunctional aziridines supplied by EIT, Inc. under the trade
designation XAMA, including XAMA-2, which is identified as
trimethylol propane-tris (beta-(N-aziridinyl) proprionate), and, in
particular, XAMA-7, which is identified as
pentaerythritol-tris-(beta-(aziridinyl) propioanate); a product of
Sybron Chemicals, under the tradename lonac including PFAZ-322,
identified as a trifuncional aziridine; and including CX-100, a
product of Zeneca Resins, identified as a polufunctional aziridine.
Desirable amounts of aziridine and/or polyisocyanate modifiers is
from about 1 to about 10 or about 15 weight percent, and more
desirably from about 2 or about 3 to about 8 or about 9 weight
percent. This can also be expressed as from about 0.5 to about 20
phr, preferably from about 1 to about 17 phr, and most preferably
from about 2 to about 15 phr. Polyisocyanates in general are
described in more detail in U.S. Pat. No. 5,268,400 column 6 lines
59 through column 7 line 17. A specific diisocynate, which can be
used is diphenylmethane diisocynate such as that sold by ICI
Americas of Wst Deptford, N.J., under the tradename "Rubinate R
MF-1780. Additionally, a suitable diisocynate is Lupranate MP102,
solvent free urethane-modified diphenylmethane diisocynate from
BASF. Desirable amounts of polytetrafluorethylene (PTFE) (and/or
perfluoropolyether (PFPE)) is from about 0.5 to about 1 or about 2
weight percent, more desirably from about 0.6 or about 0.7 to about
1.8 or about 1.3 weight percent. This can also be expressed as from
about 0.5 to about 20 phr, preferably from about 3 to about 15 phr,
and most preferably from about 5 to about 12 phr. A suitable fine
particle PTFE powder (having an average particle size by Coulter
Counter of less than microns) is sold under the tradename "Marzon
#5 by Marshall Products Company of West Chester Pa. It is
preferable to use a linear low density polyethylene such as sold by
Equistar of Houston Texas under the tradename FN 510. It is
preferable to use it in amounts of from about 3 to about 20 phr,
more preferably from about 4 to about 17, and most preferably from
about 5 to about 15 phr/Fumed silica could be used at from about
0.5 to about 20 phr, preferably from about 1 to 10 phr.
[0031] Other optional components to a molding composition include
urethane based or urethane containing oligomers or polymers, low
shrinkage additives like polyvinyl acetate or polyethylene; fibrous
reinforcing agents such as cotton glass microfibers or graphite
microfibers; flexibilizing agents; mold release agents;
polymerization inhibitors to inhibit premature polymerization
during storage or the initial stages of molding; viscosity
modifiers like fumed silica; and mold lubricant like stearates of
calcium, zinc or magnesium. Carbon black may be added to influence
the surface conductivity and to change the appearance of the molded
product. Suitable carbon blacks include an electrically conductive
low residue carbon black having a nitrogen surface area m2/g of
270, a STSA surface Area m2/g of 145 a sieve residue at 35 mesh of
0 ppm and at 325 mesh of 20 ppm as sold under the tradename
Conductex 975 by Columbia Chemicals of Jamesburg, N.J. Also,
suitable conductive carbon black is supplied by Akzo Nobel
Chemicals of Chicago, Ill. under the tradename Ketjenblack EC-300 J
and EC-600JD. Cabot Corporation of Boston Mass. also supplies a
conductive carbon black. Wherever possible given enough other
information take out the product designation. It is noted that
polyethylene and fumed silica can function as the rheological
modifier in addition to the foregoing functions.
[0032] As a further embodiment of the invention, low shrink
additives can advantageously be added to improve the surface
characteristics and the dimensional stability of the resulting
products. As previously mentioned "low profile additives" are also
encompassed within this aspect of the invention. These additives
generally include thermoplastics or elastomerics such as
homoploymers of ethylene, styrene, vinyl toluene, alkyl
methacrylates, polyethylene ether, polyphenylene oxide and alkyl
acrylates. Additional examples include copolymers using the
foregoing and in addition, vinyl chloride, vinyl acetate,
acrylonitrile, and butadiene. In particular these co-polymers would
advantageously include copolymers of vinyl chloride and vinyl
acetate; styrene and acrylonitrile; methyl methacrylate and alkyl
esters of acrylic acid; methyl methacrylate and styrene; methyl
methacrylate and acrylamide; and SBS block copolymers. These
additives are generally used in the range of 10 to 50 weight
percent based on the total weight of the additive and the resin
system, i.e. the resin and any monomers. More preferably this range
would be 20 to 45 weight percent, with a particularly preferred
range of about 30 to 40 weight percent. These additives are usually
added with the resin blending. As necessary the cure system may be
adjusted to compensate for the presence of the additive.
[0033] The molding compositions may be formulated and mixed using a
variety of mixing conditions including either continuous or batch
and using a variety of known mixing equipment. Specific examples
are set forth in the example section. The compositions may be
advantageously stored for reasonable times before molding. The
compositions can be molded by a variety of methods including
compression molding and injection molding. The compositions can be
molded under typical conditions for these types of molding
including at pressures from about 400 to about 5000 psi, and
preferably from about 2000 to about 3500 psi, and most preferably
from about 2500 to about 3000 psi and temperatures at from about
225 to about 400 degrees Fahrenheit. Dwell times are from about 50
seconds to about four minutes. The compositions are useful for
molding complex configurations including thin or intricate
conductive articles such as those having a thickness from about
0.020 to about 0.200 inches, and more preferably from about 0.040
to about 0.150 inches. The compositions are useful for articles
having bulk conductivity of at least 40, 50, 60, 70, 80, 85, 90 or
even 96 S/cm at a thickness given above. The articles from the
composition desirably have tensile strength from about 2000 to
about 6000 psi as measured in accordance with ASTM test No.D638 and
flexural modulus from about 3000 to about 10,000 psi when tested in
accordance with ASTM test no. D790.
[0034] Molded products made from the compositions of the present
invention are useful for a variety of applications demanding
complex configurations, conductivity, as well as strength, and
corrosion resistance. One particularly advantageous product, which
can be made by compression molding, is a bipolar plate for use in
fuel cells. An example of such a plate is shown in FIG. 1. The
drawing of this plate is intended to illustrate the molding
capabilities of the conductive compound of the present invention.
It is not necessarily intended to provide optimal, or even
operative, field flow design. It should not limit the invention in
any way. The plate 10 includes a fluid flow face with one or more
generally parallel and or serpentine flow channels 12. The flow
channels receive and transmit fluids through ports 14 and 16, which
are in fluid communication with corresponding entry and exit fluid
manifolds 18 and 19. The plate has a dimension, which will vary
from 1 to 20 inches in length and width, and having a thickness of
0.02 to 0.3 inch, with a cross-sectional depth of the flow channel
in the range of about 0.005 to 0.080 inch. The cross-sectional
width of a land separating adjacent flow channel sections is in the
range of 0.01 to 0.1 inch. The plate may include a number of
peripheral through holes that act as a manifold for fuel
transportation. The plate made using the compositions of the
present invention can be made substantially exclusively by molding
operations. The intricate pattern can be established without the
need for expensive, post plate production machining operations,
such as drilling, or reaming or the like.
[0035] FIG. 2 illustrates the unassembled components of a fuel
cell. This fuel cell has a base unit 12, which includes debossed
means to accept a reformer 14 and a fuel cell stack 16, which is
comprised of a plurality of bipolar plates 20 which are sandwiched
between a stack cap 22 and a stack base 24. The fuel cell further
includes a heat exchanger 26. An enclosure 30 provides a leak-proof
housing for the unit.
EXAMPLES
[0036] The following examples use the components set forth
below.
[0037] Resin A is Hetron 922 available from Ashland Chemical Co in
Columbus Ohio. It is a low viscosity epoxy vinyl ester resin. It is
about 55 wt. % solids and about 45 wt. % reactive monomer.
[0038] Resin B is Atlac 382ES from Reichhold Chemicals, Inc. in
Research Triangle Park, N.C. It is characterized as a bisphenol
fumarate resin. It was diluted to about 55 wt. % solids with
styrene.
[0039] Resin C is Dion 6694 diluted to 55 wt. % solids in styrene.
It is available from Reichhold Chemicals, Inc. It is characterized
as a modified bisphenol fumarate polyester.
[0040] Resin D is 42-2641 from Cook Composites and Polymers in
Kansas City, Mo. It was diluted to 55 wt. % solids with styrene. It
is characterized as an unsaturated polyester resin.
[0041] Resin E is ATLAC 3581-61 from Reichhold Chemicals, Inc. It
is characterized as a vinyl ester resin at 19 wt %, polyester at 27
wt % and urethane polymer at 4 wt % combined with 50 wt % styrene.
Thus, it was diluted to 50 wt % solids with styrene.
[0042] Resin F is 580-05 from Reichhold Chemicals, Inc. It is
characterized as a urethane-modified vinyl ester resin. It was
diluted to 54 wt % solids with styrene.
[0043] Resin G is 9100 from Reichhold Chemicals, Inc. It is
characterized as a bisphenol-epoxy vinyl ester. It was diluted to
54-58 wt % solids with styrene.
[0044] Resin H is Dow Derakane R8084 from Dow Chemicals, Inc. It is
characterized as an elastomer-modified vinyl ester resin. It was
diluted to 50-60 wt % solids with styrene.
[0045] Resin I is 9480-00 from Reichhold Chemicals, Inc. It is
characterized as an epoxy novolac vinyl ester. It was diluted to
53.5 wt % solids with styrene.
[0046] Resin J is Atlac 31-632 from Reichhold Chemicals, Inc. It is
an unsaturated isocyanurate vinyl ester resin.
[0047] Resin K is Dow Derakane 797 from Dow Chemicals, Inc. It is
characterized as a one pack resin which is an epoxy vinyl ester
resin containing 7-13 weight percent of divinyl benzene, 5-15
weight percent of styrene butadiene rubber co-polymer, 2-6 weight
percent of styrene homopolymer, and 0.5 to 1.5 weight percent of
styrene-ethylene oxide block copolymer, as a low profile additive.
It was diluted to 60-65 wt % solids with styrene.
[0048] Resin L is Dow Derakane 790 from Dow Chemicals, Inc. It is
also characterized as a one pack resin which is an epoxy vinyl
ester resin containing 5-15 weight percent of styrene butadiene
rubber co-polymer, 2-6 weight percent of styrene homopolymer, and
0.5 to 1.5 weight percent of styrene-ethylene oxide block
copolymer, as a low profile additive. It was diluted to 50-60 wt %
solids with styrene.
[0049] Resin M is 31633-00 from Reichhold Chemicals, Inc. It is
characterized as a isocyanurate vinyl ester resin with 4 wt %
polyether polyol It was diluted to 60 wt % solids with styrene.
[0050] Resin N is Dow Derakane 780 from Dow Chemicals, Inc. It is
also characterized as a vinyl ester resin. It was diluted to 60-70
wt % solids with styrene.
[0051] Monomer A is styrene.
[0052] Monomer B is Divinylbenzene HP from the Dow Chemical Company
and characterized as 80 wt % divinyl benzene, 18 wt %
ethylvinylbenzene, less than 0.12 wt % p-tert butylcatechol, less
than 0.5 wt % diethylbenzene and less than 1 wt % of
Napthalene.
[0053] Rheological Modifier A is Elastomag from Morton Thiokol.
Inc. in Danvers, Mass. It is characterized as 99% pure magnesium
oxide.
[0054] Rheological Modifier B is a polyisocyanate. The material
used in these experiments is 40-7263 from Cook Composites and
Polymers. It is characterized by a NCO content of 17.7 to 20.9, a
viscosity of 110-170, a flash point of 87.degree. F., and a
crystallization point of 40.degree. F.
[0055] Rheological Modifier C is RCI RD THL55 (also known as
RD-1070) from Reichhold, Inc. It is specifically a polyurethane
resin.
[0056] Rheological Modifier D is Rubinate 1780 available from ICI.
It is characterized as a polymeric methylene diphenyl
diisocyanate.
[0057] Rheological Modifier E is Marzon #5 from Marshall Products
Company of West Chester, Pa. It is characterized as a finely
divided powder polytetrafluorethylene.
[0058] Rheological Modifier F is FN-510, a linear low-density
polyethylene from Equistar Chemicals, L.P. of Houston, Tex.
[0059] Initiator A is Vazo (2,2-azo bisisobutyronitrile) available
from Dupont, I & B Industrial and Biochemical Dept, Wilmington
Del.
[0060] Initiator B is tert-butyl peroxy isopropyl carbonate
(Triginox BPIC) available from Durr Marketing in Pittsburgh,
Pa.
[0061] Initiator C is t-butylperbenzoate (TBPB) available from Durr
Marketing.
[0062] Initiator D is 1,3 di-t-butyl peroxy-3,5,5
trimethylcyclohexane catalyst (Trig 29B75) available from Durr
Marketing.
[0063] Mold release agent A is calcium stearate.
[0064] Mold release agent B is zinc stearate sold as COAD 27 by the
Norac Company, Incorporated of Azusa, Calif.
[0065] Graphite A is graphite 4012 available from Asbury Graphite
in Asbury, N.J. It is characterized by having less than 10% greater
than 150 microns and less than 10% smaller than 44 microns in
diameter.
[0066] Graphite B is SGL AshO2 characterized as a natural graphite
flake product sold by SGL Corporation.
[0067] Graphite C is XC-72.SGLV Fine characterized as a natural
graphite flake product sold by SGL Corporation.
[0068] Graphite D is available from Asbury Graphite in Asbury, N.J.
It is a modified version of the 4012 product.
[0069] Graphite E is a conductive flake graphite available from
Asbury Graphite in Asbury, N.J. under the trade designation 3243.
It is characterized by having less than 18% greater than 75 microns
and less than 65% smaller than 44 microns in diameter.
[0070] Graphite F is a conductive flake graphite available from
Asbury Graphite in Asbury, N.J. under the trade designation 230U.
It is characterized by having 100% smaller than 44 microns in
diameter.
[0071] Graphite G is a synthetic graphite available from Asbury
Graphite in Asbury, N.J. under the trade designation A99. It is
characterized by having less than 3% greater than 44 microns and
less than 99% smaller than 44 microns in diameter.
[0072] Graphite H is a synthetic graphite available under the
designation KS 75, from Timrex America, Inc. It is characterized by
having less than 95% greater than 96 microns and less than 95%
smaller than 75 microns in diameter.
[0073] Graphite I is a synthetic graphite available under the
designation KS 150, from Timrex America, Inc. It is characterized
by having at least 95% less than 180 microns in diameter.
[0074] Graphite J is a synthetic graphite available under the
designation KC44, from Timrex America, Inc. It is characterized by
having at least 90% less than 48 microns in diameter.
[0075] Carbon Black B is characterized as an electrically
conductive low residue carbon black having a nitrogen surface area
m2/g of 270, a STSA surface Area m2/g of 145 a sieve residue at 35
mesh of 0 ppm and at 325 mesh of 20 ppm as sold under the tradename
Conductex 975 by Columbia Chemicals of Jamesburg, N.J.
[0076] Carbon Black C is conductive carbon black supplied by Cabot
Corporation of Boston, Mass. under the tradename, Black Pearls,
while Graphite D is supplied by this company under the designation
XC-72.
[0077] Carbon Black E is conductive carbon black supplied by Akzo
Nobel Chemicals of Chicago, Ill. under the tradename Ketjenblack
EC-300 J and EC-600JD. EC-300 J has an iodine absorption of 740-840
mg/g; a pore volume of 310-345 cm3/100 g and an apparent bulk
density of 125-145 kg/m3. EC-600 JD has an iodine absorption of
1000-1150 mg/g; a pore volume of 480-510 cm3/100 g and an apparent
bulk density of 100-120 kg/m3.
[0078] The Glass fibers were from Owens-Corning Fiberglass and are
characterized as continuous glass filaments hammermilled into a
specific length used as a reinforcing and filler medium.
[0079] The inhibitor was 2,6-di-tertbutyl-p-cresol (25% in vinyl
toluene).
[0080] Low profile additive A is FN-510, a linear low-density
polyethylene from Equistar Chemicals, L.P. of Houston, Tex.
[0081] Low profile additive B is SGP-70C from Esprit Chemical of
Sarasota, Fla. It is characterized as a styrene divinyl benzene
copolymer with 0.4 wt % styrene monomer and 0.1 wt % divinyl
benzene.
[0082] Low profile additive C is R-134 from Premix, Inc of North
Kingsville, Ohio. It is characterized as a styrene and
thermoplastic solution with 70-80 wt % resin and styrene monomer
and 20-30 wt % styrene butadiene styrene and styrene ethylene
propylene copolymer.
[0083] Low profile additive D is Resin RP-700 from Owens-Corning
Fiberglas. It is characterized as a styrene solution of polymethyl
methacrylate with 30-35 wt % resin, and styrene.
[0084] Low profile additive E is Neulon polyester modifier T-plus
from Union Carbide. It is characterized as a polyvinyl
acetate/ester epoxide with less than 4 wt % acetate, greater than 5
wt % ester, epoxide, greater than 20 wt % polyvinyl acetate
copolymer, and less than 60 wt % styrene.
[0085] Low profile additive F is Microthene F from Equistar
Chemicals, L.P. of Houston, Tex. It is characterized as a microfine
polypropylene powder having an average particle size of 20
microns.
[0086] Low profile additive G is Levapren 450 from Bayer
Corporation. It is characterized as an ethylene-vinyl acetate
copolymer in styrene.
[0087] Low profile additive H is XLP-1889 from Union Carbide. It is
characterized as an acetic acid ethenyl ester, homopolymer in
styrene with 0.5 wt % ketone, 0.5 wt % vinyl acetate, greater than
10 wt % ether ester, less than 34 wt % polyvinyl acetate and
greater than 55 wt % styrene.
[0088] Low profile additive I is Neulon conductive E from Union
Carbide. It is characterized as a carbon black/vinyl resin compound
with greater than 70 wt % of carboxyl modified vinyl resin, less
than 30 wt % of carbon black, less than 2 wt % vinyl acetate, and
less than 1.5 wt % ketone.
[0089] Low profile additive J is RCI 31703, (Polylite R) from
Reichhold, Inc. It is characterized as a urethane pre-polymer
having 75 wt % polymer solids and 25 wt % styrene monomer.
[0090] Low profile additive K is PPO MX5587 from GE Plastics
Canada, Ltd. It is characterized as a capped PPO resin, which is a
modifed polyphenylene ether resin.
[0091] Low profile additive L is PPO SAl 20 from GE Plastics
Canada, Ltd. It is characterized as a PPO resin which is a
polyphenylene ether resin.
[0092] The molding compositions are generally prepared by adding
the resin, monomer, initiator, inhibitor, mold release agent, and
rheological modifier (if present) to a high shear cowels disperser
and blending for 2 minutes. The conductive filler is added to the
mix in a Baker Perkin, Littleford, or Readco Continuous mixer and
mixed 10 to 15 minutes. When mixing is complete the composition is
put in a suitable barrier bag and allowed to mature for
approximately one day before molding.
[0093] The molding parameters for the molding compositions are as
follows: Molding temperature for plaques was 295.degree. F. with a
molding time of 3 minutes and a charge weight of 173 g. The molding
temperature for prototype bipolar plates was 290.degree. F. with a
molding time of 3 minutes and a charge weight of 300 g. These
plates were highly detailed including an elaborate flow maze having
about a 10 to 40 thousandth depth and corresponding width as
typified in FIG. 1.
[0094] It was observed that the use of specific thermosetting
resins with a conductive filler in combination with various
rheological additives (thickeners) improved the bipolar plate
composition in regards to having a product which can be used in
mass production of electrochemical, e.g. fuel, cell bipolar
plates.
[0095] The results of the formulation changes include non-cracking
molding compound, better hot strength out of the mold, lower
production costs, shorter cycle times, better overall electrical
conductivity, increased mechanical properties, and better
rheological characteristics.
[0096] In Table IA the Control L-23012 provided a compression
molded plate, having an intricate flow field design formed therein,
useful as a fuel cell plate. However, the plate suffered from
cracking during molding and had non-uniform conductivity and
resistivity along the surface of the plate due to phase separation
of the conductive filler and resin during molding compared with a
preferred embodiment described herein in which the molded
composition contains a Theological modifier. Samples L-23185,
L-23120, L-23119 and L-23126 had desirable properties.
[0097] In Table IB Samples L-23125, L-23186, L-23039 had desirable
properties. Samples L-23184 and L-23022 had lower than optimal bulk
conductivity and higher than optimal resistivity.
[0098] In Table IC Samples L-23023, L-23063, L-23024, L-323027, and
L-23026 had lower than optimal bulk conductivity and higher than
optimal resistivity.
[0099] In Table ID Samples L-23209 and L-23215 had good properties.
Samples L-23028, L-23210, and L-23211 had lower than optimal bulk
conductivity and higher than optimal resistively.
1TABLE IA Control Component L-23012 L-23185 L-23120 L-23119 L-23126
Resin A 30.1 g Resin B Resin C 19.95 g Resin D 17.13 15.63 23.33
Initiator 0.6 g (A) 0.4 (B) 0.4 (B) 0.4 (B) 0.4 (B) Inhibitor 0.1
0.1 0.1 0.1 0.1 Mold 1.2 1.2 1.2 1.2 1.2 Release Graphite A 68 g 75
78 78 Graphite B 68 Graphite C Thickener A -- 0.35 g Thickener B --
6.17 4.67 6.97 Glass fibers Bulk 85 85 90 90 70 Conductivity S/cm
Areal 300 260 260 260 220 Conductivity S/cm.sup.2 Tensile psi 3500
3700 3600 3100 3500 Flexural psi 4100 5500 4300 3500 4200
Resistivity 70.9 87.51 71.2 37.7 OHMS/M.sup.2
[0100]
2TABLE IB Component L-23125 L-23186 L-23039 L-23184 L-23022 Resin A
Resin B 19.95 29.95 Resin C 22.65 27.65 Resin D 23.33 g Initiator
04 (B) 0.4 (C) 0.4 (B) 0.4 (C) 0.4 (B) Inhibitor 0.1 0.1 0.1 0.1
0.1 Mold 1.2 1.3 1.2 1.3 1.2 Release Graphite A 34 70 68 70 68
Graphite B 34 Graphite C Thickener A 0.55 0.35 0.55 0.35 Thickener
B 6.97 Glass fibers 5 10 Bulk 70 70 65 45 40 Conductivity S/cm
Areal 210 210 200 140 140 Conductivity S/cm.sup.2 Tensile psi 3400
3000 2800 3000 4100 Flexural psi 4200 3700 3800 4000 5000
Resistivity 58.13 123.8 117.6 155.6 222.1 OHMS/M.sup.2
[0101]
3TABLE IC Component L-23023 L-23063 L-23024 L-23027 L-23026 Resin A
Resin B 29.95 29.95 29.95 Resin C 29.95 29.950 Resin D Initiator
0.4 (C) 0.4 (B) 0.4 (D) 0.4 (C) 0.4 (B) Inhibitor 0.1 0.1 0.1 0.1
0.1 Mold 1.2 1.2 1.2 1.2 1.2 Release Graphite A 68 68 68 68 68
Graphite B Graphite C Thickener A 0.35 0.35 0.35 0.35 0.35
Thickener B Glass fibers Bulk 40 40 35 30 30 Conductivity S/cm
Areal 140 120 130 90 90 Conductivity S/cm.sup.2 Tensile psi 4200
3500 3100 4700 4300 Flexural psi 4900 4200 3400 6000 5300
Resistivity 205.9 -- 181.7 320.9 246.8 OHMS/M.sup.2
[0102]
4TABLE 1D Component L-23028 L-23209 L-23210 L-23211 L-23215 Resin A
Resin B Resin C 29.95 28.65 22.65 Resin D 21.49 21.49 Initiator 0.4
(D) 0.4 (B) 0.4 (B) 0.4 (B) 0.4 (B) Inhibitor 0.1 0.1 0.1 0.1 0.1
Mold 1.2 1.2 1.2 1.3 1.3 Release Graphite A 68 42 42 43 70 Graphite
B 26 Graphite C 0.35 26 26 Thickener A 0.35 0.55 0.55 Thickener B
8.81 8.81 Glass fibers Bulk 30 77 25 45 79 Conductivity S/cm Areal
100 227 74 132 233 Conductivity S/cm.sup.2 Tensile psi 3800 2700
3900 3000 2600 Flexural psi 5100 3900 5500 4500 4300 Resistivity
220.9 62.02 377.8 186.46 102.74 OHMS/M.sup.2
[0103]
5TABLE 2A Component 23012 23039 23022 23023 23063 Resin A 100 Resin
B 100 100 100 100 Initiator A 1.99 Initiator B 2.01 1.34 1.34
Inhibitor 1.34 Release 3.99 6.02 4.01 4.01 4.01 Agent Graphite A
225.91 340.85 227.05 227.05 227.05 Modifier A 1.17 1.17 1.17 Fiber
A 50.13 Bulk 85 65 40 40 40 Conductivity S/cm Areal 300 200 140 140
120 Conductivity S/cm.sup.2 Tensile psi 3500 2800 4100 4200 3500
Flexural psi 4100 3800 5000 4900 4200
[0104]
6TABLE 2B Component 23024 23119 23186 23184 23027 Resin B 100 Resin
C 100 100 100 100 Initiator B 2.01 Initiator C 1.77 1.45 1.34
Initiator D 1.34 Inhibitor 0.33 0.50 0.44 0.36 0.33 Release 4.01
6.02 5.74 4.70 4.01 Agent Graphite A 227.05 390.98 309.05 253.16
227.05 Modifier A 1.17 1.75 2.43 1.99 1.17 Fibers A Bulk 22.08
Conductivity S/cm Areal 35 90 70 45 30 Conductivity S/cm.sup.2
Tensile psi 135 260 210 140 90 Flexural psi 3100 3100 3000 3000
4700
[0105]
7TABLE 2C Component 23026 23028 23211 23215 23185 Resin C 100 100
100 100 Resin D 100 Initiator B 1.34 1.40 1.77 2.34 Initiator D
1.34 Inhibitor 0.33 0.33 0.35 0.44 0.58 Release 4.01 4.01 4.54 5.74
7.01 Agent Graphite A 227.05 227.05 150.09 309.05 437.83 Graphite C
90.75 Modifier A 1.17 1.17 1.92 2.43 Modifier B 36.02 Fiber B 22.08
Bulk 30 30 45 79 85 Conductivity S/cm Areal 90 100 132 233 260
Conductivity S/cm.sup.2 Tensile psi 4300 3800 3000 2600 3700
Flexural psi 5300 5100 4500 4300 5500
[0106]
8TABLE 2D Component 23120 23126 23125 23209 23210 Resin D 100 100
100 100 100 Initiator A 2.56 1.71 1.71 1.86 1.86 Inhibitor 0.64
0.43 0.43 0.43 0.47 Release 7.68 5.14 5.14 5.58 5.58 Agent Graphite
A 499.04 145.74 195.44 195.44 Graphite B 291.47 145.74 20.99
Graphite C 120.99 Modifier B 29.88 29.88 29.88 41.00 41.00 Bulk 90
70 70 77 25 Conductivity S/cm Areal 260 220 210 227 74 Conductivity
S/cm.sup.2 Tensile psi 3600 3500 3400 2700 3900 Flexural psi 4300
4200 4200 3900 5500
[0107]
9TABLE 3A Component 23227 23236 23274 23275 23293 Resin D 100 100
100 100 100 Initiator B 1.56 1.44 1.51 2.34 2.34 Inhibitor 0.52
0.48 0.50 0.58 0.58 Release 6.24 5.77 6.06 7.01 7.01 Agent Graphite
A 390.02 350.96 68.50 420.32 420.32 Carbon A 17.51 Modifier B 21.68
22.12 28.22 36.02 36.02 Fiber C 11.68 Bulk 90 Conductivity S/cm
Tensile psi 2672 Flexural psi 6543
[0108]
10TABLE 3B Component 23292 23293 23343 23344 23345 Resin D 100 100
100 100 100 Initiator B 1.48 1.56 1.44 1.29 1.20 Inhibitor 0.49
0.52 0.48 0.43 0.40 Release 5.93 6.24 5.75 5.14 4.80 Agent Graphite
A 370.74 395.22 349.78 299.91 72.22 Modifier B 15.67 16.48 21.71
21.68 21.70 Bulk 72.5 58 Conductivity S/cm Tensile psi 2170 2547
2448 2679 Flexural psi 4616 6503 5423 5897
[0109]
11TABLE 3C Component 23346 23347 23348 23349 23350 Resin D 100 100
100 100 100 Initiator B 1.09 1.02 0.95 0.90 0.84 Inhibitor 0.36
0.34 0.32 0.30 0.28 Release 4.37 4.23 3.80 3.61 3.36 Agent Graphite
A 236.79 216.57 90.11 174.70 154.19 Modifier B 21.68 21.69 21.67
21.69 21.67 Tensile psi 3083 3053 2923 3107 3470 Flexural psi 5715
5766 5666 5398 5378
[0110]
12TABLE 3D Component 23335 23352 23360 23361 23362 Resin D 100 100
100 100 100 Initiator B 0.80 0.75 2.27 2.21 2.14 Inhibitor 0.27
0.25 0.57 0.55 0.54 Release 3.22 3.02 6.81 6.62 6.43 Agent Graphite
A 142.05 125.75 425.41 413.45 02.14 Modifier B 21.68 21.73 32.16
28.45 24.93 Bulk 85.5 Conductivity S/cm Tensile psi 2787 2629 2155
Flexural psi 6167 5998 6017
[0111]
13TABLE 4A Component 23364 23365 23366 23367 23368 Resin D 100 100
100 100 100 Monomer A 9.72 8.18 7.05 6.20 5.53 Initiator B 1.46
1.23 1.06 0.93 0.83 Inhibitor 0.49 0.41 0.35 0.31 0.28 Release 5.83
4.91 4.23 3.72 3.32 Agent Graphite A 340.30 265.85 211.57 170.54
138.31 Modifier B 28.43 28.34 28.35 28.37 28.35 Bulk 55.99 36.57
32.86 18.37 13.59 Conductivity S/cm Tensile psi 2647 2697 2701 2880
2992 Flexural psi 6044 6131 6149 7002 7338 Density 1.75 1.74 1.71
1.72 1.71 g/cm3 Shrink -2.5 -2.83 -3.17 -3.33 -3.83 mils/in
[0112]
14TABLE 4B Component 23369 23370 23371 23372 23373 Resin D 100 100
100 100 100 Initiator B 1.36 1.15 1.00 0.89 0.79 Release 5.42 4.61
4.01 3.55 3.18 Agent Graphite A 316.17 249.52 200.33 162.48 132.45
Modifier B 28.27 28.21 28.21 28.21 28.21 Bulk 49.49 27.74 25.05
14.01 8.12 Conductivity S/cm Tensile psi 2974 3358 3014 2952 3154
Flexural psi 6394 6099 6520 6312 6071 Density 1.72 1.76 1.69 1.73
1.72 g/cm3 Shrink -3.5 -2.5 -2.83 -3.17 -3.53 mils/in
[0113]
15TABLE 4C Component 23443 23444 23445 23466 23467 Resin D 100 100
100 100 100 Initiator B 1.84 1.72 1.56 1.81 1.54 Inhibitor 0.46
0.43 0.39 0.45 0.39 Release 5.52 5.15 4.69 5.44 4.62 Agent Graphite
A 32.14 291.85 253.91 317.17 250.29 Modifier B 30.23 30.04 30.08
28.23 28.23 Bulk 36 21.2 15 39 21 Conductivity S/cm Tensile psi
2312 2765 Flexural psi 6154 5994 Density 1.76 1.76 1.75 1.75 1.73
g/cm3 Shrink -2 -2 -2.33 -1.67 -1.83 mils/in
[0114]
16TABLE 4D Component 23468 23469 23470 23471 23472 Resin D 100 100
100 100 100 Initiator B 1.69 1.75 1.95 2.11 1.46 Inhibitor 0.42
0.44 0.49 0.53 0.37 Release 5.52 5.15 4.69 5.44 4.62 Agent Graphite
A 287.77 284.46 331.55 369.39 241.01 Modifier B 28.23 28.23 28.23
28.23 23.47 Fiber D 17.51 19.50 21.11 Bulk 34 45 60 61 Conductivity
S/cm Tensile psi 2466 2804 1797 2010 2821 Flexural psi 5272 7390
6682 4726 4898 Density 1.71 1.6 1.62 1.58 1.75 g/cm3 Shrink -2.33
-2 -1.42 -1.67 -2.5 mils/in
[0115]
17TABLE 5A Component 23506 23507 23508 23509 23510 Resin D 100 100
100 100 100 Initiator B 1.63 1.75 1.45 1.59 1.70 Inhibitor 0.41
0.44 0.36 0.40 0.43 Release 4.89 5.24 4.34 4.77 5.11 Agent Graphite
A 277.10 305.41 235.17 270.38 298.00 Modifier B 23.47 23.47 20.48
20.48 20.48 Bulk 55 45 52 60 65 Conductivity S/cm Tensile psi 2680
2645 2483 Flexural psi 4556.7 5264.4 4773.67 Density 1.74 1.74 1.79
1.78 1.76 g/cm3 Shrink -2.5 -2.33 -2.33 -2.42 -1.75 mils/in
[0116]
18TABLE 5B Component 23566 23567 23568 23581 23582 Resin D 100 100
100 100 100 Initiator B 1.85 1.79 1.75 1.77 1.83 Inhibitor 0.46
0.45 0.44 0.44 0.46 Release 5.54 5.38 5.26 5.30 5.50 Agent Graphite
A 346.42 336.32 328.95 313.33 329.820 Modifier B 20.48 20.48
Modifier D 7.62 4.48 2.19 Bulk 92 94 Conductivity S/cm Density 1.77
1.78 1.75 1.79 1.76 g/cm3 Shrink -1.67 -1.25 -1.25 -1.67 -1.58
mils/in
[0117]
19TABLE 5C Component 23583 23584 23585 23592 23593 Resin D 100 100
100 100 100 Initiator B 1.90 1.98 2.07 1.88 1.97 Inhibitor 0.48
0.50 0.52 0.47 0.49 Release 5.71 5.95 6.20 5.63 5.91 Agent Graphite
A 347.62 366.88 387.80 352.11 369.46 Modifier B 20.48 20.48 20.48
Modifier D 9.39 14.78 Bulk 88 59 Conductivity S/cm Density 1.78
1.75 1.71 1.71 1.71 g/cm3 Shrink -1.5 -1.25 -1.25 -1.67 -1.67
mils/in
[0118]
20TABLE 5D Component 23594 23721 23722 23723 23724 Resin D 100 100
100 100 100 Initiator B 2.07 2.19 2.24 1.94 2.00 Inhibitor 0.52
0.55 0.56 0.48 0.50 Release 6.22 6.57 6.71 5.82 6.00 Agent Graphite
A 347.62 366.88 387.80 352.11 369.46 Modifier B 27.53 30.24 22.70
26.56 Modifier D 20.73 Bulk 86 93 68 65 Conductivity S/cm Density
1.71 1.74 1.77 1.77 1.78 g/cm3 Shrink -1.25 -1.42 -1.08 -1.5 -1.25
mils/in
[0119]
21TABLE 6A Component 23725 23726 23727 23728 23729 Resin D 100 100
100 100 100 Initiator B 2.14 1.90 2.14 1.90 2.14 Inhibitor 0.54
0.48 0.54 0.48 0.54 Release 6.43 5.71 6.43 5.71 6.43 Agent Graphite
D 402.14 347.62 Graphite E 402.14 347.62 Graphite F 402.14 Modifier
B 24.93 20.48 24.93 20.48 24.93 Bulk 96 75 81 62 Conductivity S/cm
Density 1.77 1.78 1.77 1.81 1.8 g/cm3 Shrink mils/in -1.67 -2.33
-0.83 -1.5 -1.
[0120]
22TABLE 6B Component 23730 23731 23732 23733 23734 Resin D 100 100
100 100 100 Initiator B 1.90 2.14 1.90 2.14 2.14 Inhibitor 0.48
0.54 0.48 0.54 0.54 Release 5.71 6.43 5.71 6.43 6.43 Agent Graphite
A 249.33 249.33 Graphite E 152.82 Graphite F 347.62 152.82 Graphite
G 402.14 347.62 Modifier B 20.48 24.93 20.48 24.93 24.93 Bulk 32 30
48 25 Conductivity S/cm Density 1.81 1.81 g/cm3 Shrink mils/in
-1.33 -1.83
[0121]
23TABLE 6C Component 23735 23736 23737 23738 23739 Resin D 100 100
100 100 100 Initiator B 2.14 2.14 1.90 1.90 1.90 Inhibitor 054 0.54
0.48 0.48 0.48 Release 6.43 6.43 5.71 5.71 5.71 Agent Graphite A
249.33 249.33 215.52 215.52 215.52 Graphite D 152.82 Graphite E
132.10 Graphite F 347.62 132.10 Graphite G 152.82 132.10 Modifier B
24.93 24.93 20.48 20.48 20.48 Bulk 38 90 50 26 31 Conductivity S/cm
Density 1.79 1.67 1.79 1.8 1.8 g/cm3 Shrink mils/in -2.08 -1.58
-1.83 -2.33 -2.67
[0122]
24TABLE 6D Component 23740 23755 23756 23757 23758 Resin D 100 100
100 100 100 Initiator B 1.90 2.17 2.20 1.93 1.95 Inhibitor 0.48
0.54 0.55 0.48 0.49 Release 5.71 6.52 6.61 5.78 5.85 Agent Graphite
A 215.52 407.61 413.22 341.81 356.10 Graphite D 132.10 Modifier B
20.48 23.91 22.87 19.52 18.54 Modifier D 2.72 5.51 2.41 4.88 Bulk
68 70 97 92 89 Conductivity S/cm Density 1.75 1.67 1.79 1.8 1.8
g/cm3 Shrink mils/in -2.08 -1.58 -1.83 -2.33 -2.67
[0123]
25TABLE 7A Component 23803 23804 23805 23806 23830 Resin D 100 100
100 100 100 Initiator B 2.06 2.09 2.18 2.19 2.16 Inhibitor 0.52
0.52 0.54 0.55 0.54 Release 6.19 6.27 6.49 6.58 6.49 Agent Graphite
A 376.29 381.20 394.59 405.48 394.59 Modifier B 25.26 25.59 25.59
26.30 30.00 Modifier E 5.15 6.53 10.81 6.85 6.76 Bulk 62 83 83 90
Conductivity S/cm
[0124]
26TABLE 7B Component 23831 23832 23833 23834 23835 Resin D 100 100
100 100 100 Initiator B 2.11 2.16 2.23 2.09 2.09 Inhibitor 0.53
0.54 0.56 0.52 0.52 Release 6.33 6.54 6.69 6.27 6.27 Agent Graphite
A 385.22 397.82 406.69 Graphite H 381.20 Graphite I 381.20 Modifier
B 25.59 25.61 25.63 25.59 25.59 Modifier E 6.81 6.96 6.53 6.53
[0125]
27TABLE 7C Component 23836 23837 23838 23839 23840 Resin D 100 100
100 100 100 Initiator B 2.09 2.24 2.24 2.24 2.24 Inhibitor 0.52
0.56 0.56 0.56 0.56 Release 6.27 6.71 6.71 6.71 6.71 Agent Graphite
A 408.28 408.28 408.28 408.28 Graphite J 381.20 Carbon B 0.56
381.20 Carbon C 0.56 Carbon D 0.56 Carbon E 0.56 Modifier B 25.59
25.56 25.56 25.56 25.56 Modifier E 6.53 6.99 6.99 6.99 6.99
Modifier F 8.39 8.39 8.39 8.39
[0126]
28TABLE 7D Component 23878 23879 23880 23881 23896 Resin D 100 100
100 100 100 Initiator B 2.26 2.37 2.28 2.39 1.48 Inhibitor 0.57
0.59 0.57 0.60 0.49 Release 6.79 7.11 6.83 7.16 5.93 Agent Graphite
A 418.55 444.31 421.41 447.49 370.74 Modifier B 25.57 25.59 25.57
25.60 5.68 Modifier C 9.99 Modifier E 7.12 7.46 Modifier F 11.88
12.44 5.69 5.97
[0127]
29TABLE 8A Component 23297 23301 23302 23363 23422 Resin E 100 100
100 100 100 Initiator B 1.56 1.38 1.33 1.06 1.75 Inhibitor 0.52
0.46 0.44 0.35 0.58 Release 6.24 5.50 5.31 4.24 7.00 Agent Graphite
A 395.22 343.88 331.86 240.03 466.74 Modifier B 5.98 2.66 1.28 2.65
2.68 Modifier C 10.50 4.63 2.26 4.66 4.67 Bulk 72.5 35 Conductivity
S/cm Density 1.62 1.53 1.6 g/cm3 Shrink mils/in -2.33 -1.33
-0.92
[0128]
30TABLE 8B Component 23423 23452 23453 23454 23455 Resin D 50.03
60.00 70.03 80.00 Resin E 100 Resin F 49.97 40.00 29.97 20.00
Initiator B 2.40 2.14 2.14 2.14 2.14 Inhibitor 0.80 0.54 0.54 0.54
0.54 Release 9.61 6.43 6.43 6.43 6.43 Agent Graphite A 680.54
402.14 402.14 402.14 402.14 Modifier B 2.64 24.93 24.93 24.93 24.93
Modifier C 4.64 Bulk 63 70.5 70 83.5 Conductivity S/cm Tensile psi
2441 2497 2404 2561 Flexural psi 5030 5126 4284 5391 Density 1.47
1.71 1.74 1.75 1.66 g/cm3 Shrink mils/in -0.25 -1.17 -1.58 -1.67
-1.42
[0129]
31 TABLE 8C Component 23530 23531 23646 23647 23648 Resin F 100 100
Resin G 100 100 100 Initiator B 1.85 1.79 1.81 1.91 2.02 Inhibitor
0.46 0.45 0.45 0.48 0.50 Release 5.54 5.38 5.42 5.72 6.06 Agent
Graphite A 346.42 336.32 338.75 357.65 378.60 Modifier B 5.24 11.11
17.62 Modifier D 7.62 4.48 Bulk 86 58 46 Conductivity S/cm Tensile
psi 2305.56 2155.56 Flexural psi 4548.8 4421.3 Density 1.69 1.75
1.71 1.72 1.65 g/cm3 Shrink mils/in -0.42 -1 .67 -1.58 -1 .42
-1.33
[0130]
32 TABLE 8D Component 23649 23650 23651 23688 Resin I 100 100 100
Resin J 100 Initiator B 1.75 1.77 1.79 1.91 Initiator D 2.08
Inhibitor 0.44 0.44 0.45 0.52 Release 5.26 5.31 5.38 6.25 Agent
Graphite A 328.95 331.86 336.32 385.42 Modifier B 15.63 Modifier D
2.19 3.10 4.48 Bulk 93 79 64 Conductivity S/cm Density 1.77 1.74
1.73 g/cm3 Shrink mils/in -1.5 -1.08 -1.5
[0131]
33 TABLE 9A Component 24004 24005 24006 24007 24008 Resin D 100
85.12 80.15 50.02 5002 Resin K 49.98 Resin L 49.98 Initiator B 1.11
1 0.99 0.99 0.98 Inhibitor 0.56 0.5 0.49 0.49 0.49 Release 6.69
5.97 5.93 5.93 5.93 Agent A Graphite A 412.26 368.16 365.43 365.43
365.43 Modifier B 18.38 15.67 14.81 14.81 14.81 Low Profile A 6.96
6.21 6.17 6.17 6.17 Low Profile B 11.14 Low Profile C 14.86 Low
Profile D 19.85 Shrink mils/in -1 -0.65 -0.45 -1.1 -1.03
[0132]
34 TABLE 9B Component 24009 24010 24011 24012 24052 Resin D 84.99
89.98 Resin K 100 Resin L 100 100 Initiator B 0.92 0.92 0.99 0.99
0.91 Inhibitor 0.46 0.46 0.49 0.49 0.46 Release 5.53 5.53 5.93 5.48
Agent A Graphite A 345.62 345.62 365.43 365.43 342.47 Modifier A
2.53 2.53 1.6 Modifier B 14.81 14.81 Low Profile A 5.76 5.76 6.17
6.17 5.71 Low Profile C 14.86 Low Profile D 15.01 10.02 Shrink
mils/in 0.34 -0.21 -1 .3 -0.89 0.02
[0133]
35 TABLE 9C Component 24053 24054 24055 24056 Resin K 100 100 Resin
L 100 100 Initiator B 0.91 0.9 0.91 0.91 Inhibitor 0.45 0.45 0.46
0.45 Release 5.45 5.43 5.48 Agent A Graphite A 340.91 339.37 342.46
340.91 Modifier B 1.14 0.68 1.6 1.14 Low Profile A 5.68 5.66 5.71
5.68 Shrink mils/in -0.02 0.21 -0.24 -0.21
[0134]
36 TABLE 10A Component 24141 24142 24149 24159 24160 Resin K 100
100 100 Resin Q 80 70 Initiator B 0.92 0.93 0.93 0.93 Initiator D
0.55 Inhibitor 0.46 0.46 0.47 0.47 0.47 Release 2.97 2.96 3.96 3.96
3.96 Agent A Release 2.97 2.96 3.96 3.96 3.96 Agent B Graphite A
343.25 342 349.65 349.65 349.65 Modifier A 1.37 1.37 1.4 1.4 0.93
Low Profile A 5.72 5.7 5.83 5.82 5.82 Low Profile E 20 29.98 Shrink
mils/in -0.89 -1.58 -0.72 -0.26 0.03
[0135]
37 TABLE 10B Component 24161 24194 24195 24196 24197 Resin D 100
100 Resin K Resin Q 60 70 70.29 Initiator B 0.93 1.03 0.93 0.93
0.93 Inhibitor 0.47 0.47 0.47 0.47 3.14 Release 3.96 7.3 3.96 3.96
3.98 Agent A Release 3.96 3.96 3.96 3.98 Agent B Graphite A 349.65
450.4 349.65 349.65 350.96 Modifier A 1.4 1.4 1.4 1.78 Low Profile
A 5.83 5.85 Low Profile E 40 30.43 29.98 29.71 Low Profile F 3.96
7.3 5.83 5.83 Shrink mils/in -0.89 -1.58 0.18 -0.45 0.07
[0136]
38 TABLE 10 C Component 24249 24250 24261 24262 24287 Resin D 70
68.83 61.53 Resin K 88.3 Resin Q 64.44 Monomer B 11.7 11.7 12.5
12.99 12.79 Initiator B 0.93 0.94 1 1.04 1.02 Inhibitor 0.47 0.47
0.5 0.52 0.51 Release 3.98 6 6.23 6.3 Agent A Release 3.98 Agent B
Graphite A 350.96 350.96 370 384.42 378.52 Modifier B 1.78 16.25
20.78 Low Profile A 5.84 5.85 6.26 6.49 Low Profile E 23.86 17.5
18.18 25.68 Shrink mils/in -0.86 -0.55 -0.93 -0.83 -0.79
[0137]
39 TABLE 10 D Component 24288 24317 24318 24319 24320 Resin D 53.84
60.53 52.47 59.04 100 Monomer B 12.54 14.66 14.37 17.18 32.72
Initiator B 1 1.17 1.15 1.37 2.62 Inhibitor 0.5 0.59 0.57 0.69 1.31
Release 6.02 7.04 6.9 8.25 15.71 Agent A Graphite A 371.3 451.61
442.53 549.83 1047.12 Modifier B 16.66 18.77 16.38 18.56 30.76 Low
Profile A 6.27 7.33 7.18 8.59 16.36 Low Profile E 33.62 24.81 33.16
23.78 62.3 Shrink mils/in -0.73 -0.34 0 0.14 -0.52
[0138]
40 TABLE 11A Component 24364 24365 24495 24496 24497 Resin D 60.53
52.47 Resin N 60.93 52.19 60.93 Monomer B 14.66 14.37 13.01 13 13
Initiator B 1.17 1.15 Initiator D 0.57 0.57 0.57 Inhibitor 0.59
0.57 0.52 0.52 0.52 Release 7.04 6.9 6.24 6.24 6.24 Agent A
Graphite A 451.61 442.53 400.62 400.62 400.62 Modifier B 18.77
16.38 5.83 Modifier D 5.83 5.83 Low Profile A 7.33 7.18 6.5 6.5 6.5
Low Profile E 26.06 34.81 Low Profile G 24.81 33.16 26.07 Shrink
mils/in -0.52 0.17 0 0.14 0.14
[0139]
41TABLE 11B Component 24498 24499 24500 24523 24524 Resin D 60.53
59.09 58.33 Resin N 52.19 60.93 Monomer B 13 13 14.66 15.2 15.48
Initiator B 1.17 1.22 1.24 Initiator D 0.57 0.57 Inhibitor 0.52
0.52 0.59 0.61 0.62 Release 6.24 6.24 7.04 7.29 7.43 Agent A
Graphite A 400.62 400.62 451.61 468.09 476.78 Modifier B 18.77 23.1
25.39 Modifier D 5.83 5.83 Low Profile 6.5 6.5 7.33 7.6 7.74 A Low
Profile 25.71 26.19 E Low Profile 34.81 H Low Profile 26.07 24.81 I
Shrink mils/ 0.23 -0.33 -0.29 -0.45 -0.66 in
[0140]
42TABLE 11C Component 24498 24499 24500 24523 24524 Resin D 60.53
79.98 69.99 Resin N 65.64 52.19 Monomer B 14.66 14.01 13 Initiator
B 1.17 1.02 1.02 Initiator D 0.62 0.57 Inhibitor 0.59 0.5 0.52 0.51
0.51 Release 7.04 6.72 6.24 6.11 6.11 Agent A Graphite A 451.61
431.61 400.62 376.97 376.97 Modifier B 18.77 18.44 18.44 Modifier D
6.28 5.83 Low Profile 7.33 7.01 6.5 6.37 6.37 A Low Profile 24.81
28.08 34.81 J Low Profile 20.02 30.01 K Shrink mils/ -1.79 -2.65
-3.02 in
[0141]
43TABLE 12 Component 24633 24634 24635 24636 Resin D 60.01 79.98
69.99 60.01 Initiator B 1.02 1 .02 1.02 1.02 Inhibitor 0.51 0.51
0.51 0.51 Release 6.11 6.11 6.11 6.11 Agent A Graphite A 376.97
376.97 376.96 376.97 Modifier B 18.44 18.44 18.44 18.44 Low Profile
A 6.37 6.37 6.37 6.37 Low Profile K 39.99 Low Profile L 20.02 30.01
39.99
[0142] The examples of Tables 9 through 12 illustrate that
acceptable shrink characteristics can be achieved using a low
profile additive. In general, these samples had a shrink
measurement of less absolute than two mils/in as measured by ASTM
D792. Further the samples had improved surface characteristics
including a smoother surface with the avoidance of roughness such
as orange peel and ripple.
[0143] In accordance with a further embodiment of the invention,
the following compositions can be used in a new molding process to
accomplish injection molding. In particular, as is illustrated in
FIG. 5, the process of the present invention involves using a
phenolic style screw 105, in a auger 106, to convey the highly
loaded molding compositions of the present invention to the feed
throat 108 of an injection molding apparatus 110. This process
contrasts to the traditional process using a hydraulic ram to port
the molding composition to the feed throat. However, the
traditional molding methods and equipment would fail with
potentially catastrophic results when the composition would pack
out during the molding process. For example, FIGS. 3 and 4 are
photographs of packing out at the feed throat, which occurred using
a highly loaded composition such as Sample 23808 in the previously
described apparatus. The composition was fed into a traditional
injection molding machine, which uses an hydraulic ram to feed the
composition from a screw barrel to the feed throat (i.e. a
restricted orifice at the mold gate.) The composition packed out in
the mold orifice.
[0144] In contrast to this situation, when the same composition was
processed using a stuffer having a hopper with a auger having a
vertical component, i.e. either substantially vertical, or at a
vertical angle with respect to the horizontal plane of the
injection molding machine, it could be molded into complex shapes
compared to that of FIG. 1 using otherwise conventional injection
molding techniques. It is more preferred that a double auger system
having a stuffer 104 which comprises a hopper 106 with a first and
larger horizontally oriented auger 120 which feeds the smaller
vertical auger 105 feeding into a modified phenolic resin type
screw in the feed throat 108 which ports directly into a single or
double gate cavity mold 109. The first auger is a standard style
and size auger; however, the vertical auger is a 90 mm outer
diameter and approximately 35 inch length auger. The tip of this
auger was modified by matching and blending into the feed throat
area to eliminate any dead spots. The otherwise standard smear tip
of the phenolic screw is modified from standard by machining to a
constant inner diameter and a constant flight depth which was
blended to a point at the end. A phenolic screw differs from other
known screw configurations by the flight range, as well as by the
fact that a phenolic screw does not include check rings. Further,
the process involves some zoned temperature gradients with a first
and second zone 122, 124 in the first screw barrel 126 each having
a temperature, which can be the same or different, of from about 70
to about 140 degrees F, and more particularly about 70 to about 100
degrees F (i.e. 70 F). It is also possible to take this temperature
lower by using a chiller. A third zone 128 is located at the mold.
This zone is maintained at about 275 to about 325 F, (i.e. 300 F)
which is the temperature at which cure is initiated for most of the
compositions in accordance with the invention. The examples were
run using the parenthetical temperatures. Current work involves
holding the first and the second zone both at 70 F. Earlier work
involved having the first zone at 90-95F and the second zone at
110-125F. It is preferable to avoid temperature variations at the
mold level. At normal cure rates, the mold time is typically around
10 to 600 seconds, or more usually 30 to 300 seconds or around one
or two minutes. The process can be practiced for single or double
gate cavity tools, or even for injection/compression processes in
which the mold is slightly opened during fill and the mold is shut
to compress the shot.
[0145] It was also found that the composition could be molded by
injection molding using an injection molding apparatus 220 shown in
FIG. 6 comprising a single auger Krauss-Maffei AZ50 or AZ100
stuffer 220 with porting directly into the feed throat 222 of the
injection molding machine 224. This machine has a angled rotating
conical hopper 230 with a rotating auger screw 232. The angle has a
vertical component in that it is between 30 and 60 degrees to the
horizontal plane, and more particularly at about 45 degrees. Thus,
this auger has a vertical component to its orientation. The stuffer
needs to be sealed or semi-sealed to avoid drying of the
compound.
EXAMPLES
[0146] Several hundred samples have been injection molded in the
double auger equipment, before and after modification, using the
process that has been described with the formulation set forth as
L-23193. These samples have been molded as planar 7 by 10 inch
rectangular test plaques using a single cavity mold and a mold time
of 2 minutes. The thickness have included 0.053 inch, 0.100 inch,
0.120 inch, and 0.140 inch. A conductivity of at least about 50
S/cm has been achieved for the 0.053 thickness samples. Further,
during the course of the development work, an improvement of at
least about 100% increase from the starting values has been
achieved, which is attributed chiefly to a reduction in shear
during processing. It appears to be preferable to achieve a matte
appearance on the finished sample.
[0147] In addition, a round disc sample has been successfully
molded using the L-23193 formulation using a Krauss-Maffei
injection molding machine with the AZ100 stuffer system.
[0148] While in accordance with the Patent Statutes, the best mode
and preferred embodiment have been set forth, the scope of the
invention is not limited thereto, but rather by the scope of the
attached claims.
* * * * *