Note: Descriptions are shown in the official language in which they were submitted.
CA 02234668 1998-04-09
WO 97/15619 PCT/US96/16960
ONE-COMPONENT CHEMICALLY URING HOT APPLIED
INSULATING GLASS SEALANT
Background of the Invention
Field of the Invention
This invention relates generally to methods and compositions relating to the
construction of insulating glass units and in particular, methods and
compositions
for making a sealant which is applied at the edges of insulating glass units
for the
purpose ofadhering the components ofthe unit together, and sealing the unit
from
subsequent moisture penetration. Most specifically, the present invention
relates
to a one-component edge sealant for insulating glass units which is applied as
a
liquid or paste at an elevated temperature, then reversibly and rapidly
solidifies
upon cooling, and thereafter irreversibly solidifies upon exposure to ambient
atmospheric conditions.
Description of the Prior Art
Insulating glass units generally comprise a pair of glass sheets maintained
in a spaced apart relationship to each other by a spacing and sealing assembly
which extends around the periphery of the inner, facing surfaces of the glass
sheets,
to define a sealed and insulating air space between the glass sheets. A spacer
assembly generally comprises an inner spacer-dehydrator element which extends
around the periphery of the inside facing surfaces of the glass sheets. The
inner
surfaces of the glass sheets are attached to the outer surface of the spacer
assembly
by means of a sealant or adhesive. Generally, the sealant or adhesive is also
used
to seal the edges of the glass unit so as to establish a barrier which
prevents
moisture from penetrating into the interior of the unit.
The two major types of sealants currently used in the insulating glass
industry are the thermoplastic one-part hot melt butyl type, and the
chemically
curing, thermoset products generally from the generic families of polysulfide,
polyurethane, and silicone. The former, or the hot melt butyl insulating glass
sealants, have been used with moderate success for a number of years in the
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WO 97/15619 PCT/US96/16960
2
insulating glass industry. However, there are significant shortcomings with
this
technology that has limited the application of hot melt butyl insulating glass
sealants. Primarily, the hot melt butyl is thermoplastic, and not thermoset.
That
is, these sealants are subject to softening when exposed to heat. Therefore,
the
insulating glass units sold in the marketplace, when placed under load, will
flow or
deform to relieve the load. This characteristic is exaggerated at high
temperatures,
which can occur in insulating glass units, especially those utilizing solar
control
glass. As a result, insulating glass units made with hot melt butyl sealants
have
di$iculty passing the industry standard test due to stress and temperature,
and can
only be used successfully in relatively small, light units. Additionally,
extreme care
must be taken to support the insulating glass unit during handling, shipping
and
installation, resulting in additional costs.
Furthermore, the hot melt sealants previously employed must be applied to
the units at temperatures exceeding 300°F. These high temperature
requirements
have resulted in worker injury, due to burns, as well as increased
manufacturing
costs due to higher energy consumption and the need for specialized, high-
temperature equipment. Any attempts to utilize lower temperature hot melts
have
resulted in greater flow problems with the sealant, as has previously been
discussed.
The thermoset products which are currently used are generally two-
component sealants which are mixed at the point of application at room
temperature. The sealants then cure slowly by reaction with the supplied
catalyst
or through reaction with moisture. This slow cure requires that the insulating
glass
units be held in inventory from several hours to days waiting for the sealant
to
harden. Additionally, these two-component systems are more difFlcult to employ
and further increase manufacturing costs because of the additional steps
involved
in their use. s
U.S. Patent No. 4,032,500 discloses a two-component, curable sealant
composition, each component being individually storage-stable. Each component
contains oil-extended low molecular weight uncured butyl rubber. The
CA 02234668 2003-04-22
1
components are mixed together just prior to use in an approximately one to one
volume ratio.
U.S. Patent No. 4,042, ;r36 discloses a single application sealant for use in
insulating glass units comprising a partially cross-linked hot melt butyl
rubber sealant.
The patent further discloses th=at complete cross-linking of the sealant will
occur when
the composition is. post heated from about 325°f to about 425°F.
Sufficient heat is
applied to the exterior face of they Sealant composition to raise the
temperature of the
outerniost portion of the seala~ut composition to this temperature range,
while the
innermost portion of the sealant composition remains at a temperature
substantially
below this temperature range.
U.S. Patent No. 4,808,~r55 discloses an extrudable reactive hot melt urethane
adhesive containing a urethane prepolymer, a tackifying resin and a
thermoplastic
resin. However, since the curing; the urethane liberates COZ gas, adhesives
utilizing a
urethane-curing chemistry are highly unsuitable for the insulating glass
industry, as
bubbles can get trapped at the interlace of the sealant and the glass.
US Patent No. 5,340,8'v 7 ( Vincent) discloses an adhesive composition
comprising a thermoplastic hydrokyl-functional organopolysiloxane
resin, a diorganopolysiloxane ~:~olymer having silicon-bonded hydroxyl
terminal
groups, a ketoximosilane and ;:gin optional catalyst.
US Patent No. 5,061,7-19 discloses a one-pack type heat pre-curable moisture-
curing sealant composition comprising a urethane prepolymer containing a
specific
amount of an active free isocy~nate group and a vinyl polymer containing a
hydrolysable siloa;y group. Tl~e siloxy group of the vinyl polymer is
hydrolyzed with
moisture in the air to produce ~i hydroxy group. The hydroxy group is then
reacted
with the active free isocyanotc group of the urethane prepalymer. The reaction
is
promoted by heating to a temperature of 40°C to 120°(' ( 129-
273°F).
The present invention ;~ec;ks to overcome the problems of the prior art in
that it
provides an edge ;sealant for u:;e in insulating glass units by providing a
silicon-
functionalized, chemically curing thennoset product with inherently high
strength and
resistance to flow, while providing the convenience of a one-part sealant with
hot
melt-type application properties. Because the present sealant employs
compatible
compositions which solidify at different rates and through different
mechanisms, the
CA 02234668 2003-04-22
present invention can be applifd at a lower temperature than traditional hot
melts, and
also provides sufficient handling strength to the unit faster than traditional
chemical-
cure products, thereby combining the best praperties of bath the hot melt and
chemically curing teclvlologie~~ into a successful sealant for the insulating
glass
industry. The sealant of the present invention is designed to be applied at
elevated
temperatures in the range of 1 ~'.5~-250°F, in the forrr~ of a liquid
or paste which turns
back to a solid im~:nediately upon cooling. 'hhe product then cures to a
permanent
solid elastomer by reaction with atmospheric oxygen and/or moisture. These and
other advantages of the present invention will be readily apparent from the
description, the discussion and e:Kamples which follow.
There is disclosed herein an edge sealant for insulating glass units
comprising
a thermoplastic hot melt resin ,:end an atmospheric cL~ring resin of the type
which
polymerizes upon exposure to an ambient atmosphere, the atmospheric curing
resin
being combined with the thermoplastic hot melt resin as a single material. The
thermoplastic hot melt resin ar5d the atmospheric curing resin can comprise
identical
compositions. The present sealant comprises, by weight, approximately 10-90%
by
weight of a therm~~plastic hot rnc;lt resin, together with 5-50% by weight of
an
atmospheric curing resin.
According to one aspect of the present invention there is provided an
insulating glass unit having a first glazing pane maintained in a spaced apart
relation
with a second glazing pane by a spacer, an edge sealant for said insulating
glass unit,
said sealant comprising:
a thermoplastic hot-melt resin, said thermoplastic hot melt resin having
a melt temperature of around ~ 25-250°F', and
an atmospheric curing resin, said atmospheric curing resin
polymerizing upon exposure tc~ a component of the atmosphere, said component
comprising a compound selected 1-rom the group consisting of oxygen vapor,
water
vapor, and mixtures thereof, said atmospheric curing resin comprising a
silicon-
containing atmospheric curing rf;sin, said atmospheric curing resin being
combined
with said thermoplastic hot melt resin as a single material, whereby said
sealant is in a
liquid phase at a temperature above around 6$-77°F, reversibly
solidifies upon
CA 02234668 2003-04-22
4a
cooling to a temperature of arou~ d 68-77°F, and irreversibly
solidifies upon
subsequent exposure to said ct>mponent of the atmosphere.
According; to a further aspect of the present invention there is provided a
one-
part edge sealant, said sealant comprising:
a thermoplastic hut melt resin, said hot melt resin having a melt
temperature of around 125-25ii°T, and
a silicon-containing atmospheric curing resin, said atmospheric curing
resin polymerizing upon exposure to a component of the atmosphere, said
component
comprising a compound selected from the group consisting of oxygen vapor,
water
vapor, and mixtures thereof, said atmospheric curing resin being combined with
said
thermoplastic hot melt resin as a single material, whereby said sealant is in
a liquid
phase at a temperature above around ~8-77°f, reversibly solidifies upon
cooling to a
temperature of around 68-77°F, and irreversibly solidifies upon
subsequent exposure
to said component: of the atmosphere.
According to another aspect of the present invention there is provided a one-
part edge sealant, said sealant s;omprising:
10-90% by weight of said sealant of a thermoplastic hot melt resin,
said hot melt resin comprising a compound selected from the group consisting
of solid
chlorinated paraffin, epoxidized Soya oil, polyisobutylene, and mixtures
thereof, and
5-50% by weight of said sealant of an atmospheric curing resin which
polymerizes upon exposure to a component of the atmosphere, said component
comprising a compound selected U:rom the group consisting of oxygen vapor,
water
vapor, and mixtures thereof, said atmospheric curing resin comprising a
compound
selected from the group consisting of an alkoxy silane terminated
polyurethane, an
organo functional silane, and mixtures thereof,
said atmospheric curing resin being combined with said thermoplastic
hot melt resin as a single material, whereby said sealant is in a liquid phase
at a
temperature above around 68-77°p, reversibly solidifies upon cooling to
a
temperature of around 68-77°F, and irreversibly solidifies upon
subsequent exposure
to said component of the atmosphere.
In some preferred embc~di.ments:
CA 02234668 2003-04-22
4b
said thermoplastic hot mc;lt resin comprises approximately 10-90% by weight
of said sealant;
said atmospheric curinresin component comprises approximately 5-50% by
weight of said sealant;
said thernioplastic hot ~ne;lt resin comprises a compound selected from the
group consisting of polyethyleoes, polyolefins, polyvinyl acetate, polyamides,
hydrocarbon resins, asphalts, hit~.~mens, waxes, paraffins, crude rubbers,
fluorinated
rubbers, polyvinyl chloride, polyamides, fluorocarbons, polystyrene,
polypropylenes, cellulosic resi~as, acrylic resins, thermoplastic elastomers,
styrene
butadiene resins, polyterpenes, ethylene propylene dime monomer, and mixtures
thereo f;
said thermoplastic hot melt resin comprises a compound selected from the
group consisting of solid chlorinated paraffin, polyisobutylene, epoxidized
soya oil,
and mixtures thereof;
said atmospheric curing resin comprises a compound selected from the group
consisting of moisture curing turethanes, moisture curing polysulfides, oxygen
curing
polysulfides, and mixtures therec>i';
said atmospheric curin,y resin comprises a compound selected from the group
consisting of alkoxy silane terminated polyurethanes, alkoxy silane terminated
polyethers, polydimethylsilox~~ne; resins, organo functional silanes, and
mixtures
thereo f;
said thermoplastic hot melt resin also functions as said atmospheric curing
resrn;
said thermoplastic hot melt resin and said atmospheric curing resin comprise a
compound selected from the group consisting of high molecular weight silicon-
containing urethane prepolymf~rs and silicon-containing acrylonitrile
butadiene
copolymers;
and the sealant further comprises a compound selected from the group
consisting of plasticizers, fillers, pigments, catalysts, weatherability
improvers, and
mixtures thereof.
CA 02234668 2003-04-22
~C
In particular embodiments, the thermoplastic hot melt resin comprises a solid
chlorinated paraffin. 'fhe atmospheric curing resin is preferably a silane
terminated
polyurethane. The sealant mdy also include ancillary ingredients such as
plasticizers,
catalysts, and fillers. Small v~olurne additives may include colorants,
rheological
materials, weatherability improvers, and/or pigments, as are known in the art.
The present invention is directed to a one-component, hot applied, chemically
curing edge sealant for insulating glass units. The purpose of the sealant is
to provide
structural integrity to the unit while sealing out moisture and preventing the
exchange
of gasses. The edge sealant also resists environmental attack from water, UV,
and
temperature extremes.l'he sealant of the present invention is designed to be
applied at
an elevated temperature of ap~~roximately 125-250°F in the forn~ of a
liquid or a paste,
which then turns back to a solid immediately upon cooling. The product then
begins
curing to a permanent solid elastomer by reaction which atmospheric moisture
CA 02234668 1998-04-09
WO 97/15619 PCT/US96/16960
and/or oxygen. The present invention combines the application properties of a
hot
melt product with its attendant rapid cooling to a solid, which allows the
immediate
handling of the insulating glass unit. The sealant of the present invention
then
cures chemically to provide a permanent elastomeric, temperature-resistant
sealant
5 which provides the structural integrity for the insulating glass unit.
The sealant of the present invention comprises a thermoplastic hot melt
resin, and an atmospheric curing resin of the type which polymerizes upon
exposure to an ambient atmosphere, the atmospheric curing resin being combined
with the thermoplastic hot melt resin as a single material. This is understood
to
mean that on a macroscopic scale, the sealant comprises a substantially
homogeneous mixture; it may also include compositional variations on a
microscopic scale. In an alternate embodiment, the thermoplastic hot melt
resin
and the atmospheric curing resin may comprise an identical composition. The
hot
melt resin functions as the meltable component during the initial application
and
supplies strength immediately upon cooling. The polymer phase then begins to
cure by reaction with atmospheric moisture to form a cross-linked thermoset
elastomer which is temperature resistant. At this point, the hot melt resin
functions
as an inert plasticizes within the cured polymer phase.
Strength properties in the hot melt phase can be controlled by the type and
quantity of the hot melt resin and filler selection. Ultimate strength of the
edge
sealant is controlled by the type and cross-linked density of the curing
polymer.
Within the context of this disclosure, atmospheric "curing resins" are meant
to
include polymeric materials which cross-link and/or polymerize upon exposure
to
a component of the ambient atmosphere, typically oxygen or water vapor.
Preferably, the thermoplastic hot melt resin is present in the sealant in a
concentration of 10-90% by weight, more preferably 30-80% by weight and most
preferably 40-65% by weight. The atmospheric curing resin is typically present
in
the sealant in a range of 5-50% by weight more preferably 10-40% by weight,
and
most preferably 18-28% by weight. The sealant may also include a catalyst,
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WO 97/15619 PCT/CTS96/16960
6
plasticizers, fillers, pigments, weatherability improvers and the like, as are
known
in the art.
The thermoplastic hot melt resin is preferably one which solidifies '
immediately upon cooling. It may fi.~rther comprise polyethylenes,
polyolefins,
polyvinyl acetate polyamides, hydrocarbon resins, asphalts, bitumens, waxes,
paraffins, crude rubbers, fluorinated rubbers, polyvinyl chloride, polyamides,
fluorocarbons, polystyrene, polypropylenes, cellulosic resins, acrylic resins,
thermoplastic elastomers, styrene butadiene resins, ethylene propylene dime
monomer, polyterpenes, and mixtures thereof. One particularly preferred
thermoplastic hot melt resin is a mixture of solid chlorinated parafl'ln and
an
epoxidized soya oil. Another preferred thermoplastic hot melt resin is a
mixture
of solid chlorinated para~n and polyisobutylene.
The atmospheric curing resin begins to cure subsequently to the cooling of
the hot melt resin by reaction with oxygen and/or atmospheric moisture to form
a
cross-linked thermoset elastomer which is temperature resistant. A preferable
group of atmospheric curing resins comprise moisture cure polyurethanes,
moisture
cure polysulfides, polydimethylsiloxanes, oxygen cure polysulfides, and
mixtures
thereof, some containing silicon functionalities. Some specific atmospheric
curing
resins include alkoxy, acetoxy, oxyamino silane terminated polyethers and
polyether urethanes; alkyl siloxane polymers crosslinked with alkoxy, acetoxy,
oxyamino organo functional silanes; moisture curable isocyanate fiznctional
polyoxyalkaline polymers and polyalkaline polymers; thiol functional polymers
and
oligomers (such as polyethers, polyether urethanes, polysulfides,
polythioethers),
suitably catalyzed to produce moisture curable systems; epoxide functional
polymers and oligomers with moisture deblockable crosslinkers; acrylic
fiznctional
polymers with deblockable crosslinkers, and mixtures thereof. Most preferably,
the
atmospheric curing resin comprises atkoxy silane terminated polyurethanes,
alkoxy
silane terminated polyethers, polydimethylsiloxane polymers, and mixtures
thereof.
In a most preferred formulation, the atmospheric curing resin comprises a
mixture
CA 02234668 2003-04-22
7
of Permapol MS (alkox:y silane terminated polyurethane, manufactured by
Courtaulds Coatings, Inc.) and an organo functional silane.
As has already been disclosed, in an alternate embodiment, the
thermoplastic hot melt :resin and the atmospheric curing resin can comprise an
identical composition. One preferred formulation comprises high molecular
weight
silicon-terminated urethacie prepolymers. Another formulation comprises
silicon-
firnctionalized Kraton lsolymers (block copolymers, manufactured by Shell).
Kraton polymers are block copolymers of several types such as SBS (styrene-
butadiene-styrene), SIS (styrene-isoprene-styrene), and SEBS (styrene-
ethylene/butylene-styrene). Yet another formulation comprises Kraton polymers
with other functional groups whiEh provide for rapid solidification upon
cooling:
followed by chemical cure upon exposure to atmospheric conditions.
The specific orga~~ic catalyst used in the present invention will depend upon
the particular atmospheric:: caring resin which is used. Preferable catalysts
comprise
IS organo tin compounds, aliphatic titanates (having from 1-12 carbon atoms)
such
as lower alkyl titanates., and amines. Most preferably the catalyst comprises
dibutyltin dilaurate, dibutylt:in diacetate, tetrabutyl titanate, and
tetraethyl titanate.
Although the sealant will still cure without the addition of the catalyst, the
addition of a catalyst may provide for faster curing times, which may be
necessary
in certain situations. It may also be desirable, in some instances, to add
additional
fillers, pigments, rheological agents and like.
Strength properties in the hot melt phase depends on the type and quantity
of the hot melt resin, and also the filler selection. One preferred filler is
talc. Other
fillers can be used, as is known in the art 'Che range of fillers may be
selected by
one of skill i:n the art and added in an amount sufficient to impart the
appropriate
strength to the hot melt please, as well as to impart desirable application
properties
to the sealant. The sealant of the present invention should be easy to handle
and
apply to the insulating glass units
The sealant of the present invention may be prepared in the following
~ 0 manner. Preferably, the thermoplastic hot melt resin, or mixtures thereof,
is first
* T~ad~rrrmsrk
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WO 97/15619 PCT/US96/16960
8
disposed in a mixing vessel at an elevated temperature. In one preferred
embodiment, the mixing vessel is capable of carrying out mixing under a vacuum
v
and which further includes a mixer that comprises a variable speed, mufti-
shaft unit,
having a low speed sweep blade, a high speed disperser, and a low speed auger.
S The filler is then added to the hot melt resin and mixing begins at low
speed.
Thereafter, the atmospheric curing resin, or mixtures thereof, to which
additional
filler has been added to form an atmospheric curing resin composition, is
added to
the mixture subsequent to turning on the vacuum. At the point the atmospheric
curing resin composition is added, the mixing is conducted under vacuum so as
to
eliminate any exposure of the mixture to atmospheric conditions, and also to
remove residual water from the raw materials, thereby improving package
stability.
Small volume additives such as pigments, weatherability improvers and the like
can
be added before the introduction of the atmospheric curing resin composition,
while any catalyst may be added after. The material is maintained under
essentially
dry conditions until such time as it is ready to be applied to the insulating
glass
unit. In other preferred embodiments, the mixing may be carried out under a
blanket of dry, inert gas.
The edge sealant of the present invention is applied to the insulating glass
unit at elevated temperatures, approximately 125-250°F in the form of a
liquid or
a paste. Thereafter the sealant rapidly but reversibly cools into a solid. The
sealant
then begins to cure to a permanent solid elastomer by reaction with
atmospheric
oxygen and/or moisture. The sealant of the present invention is applied to the
unit
as a single material, therefore eliminating the need to combine several
components
together at the point of application.
The present invention will best be illustrated by the following series of
examples:
CA 02234668 2003-04-22
9
,F.~C~~MP I~E 1
CHARGE
M8TEB181. ,~T ~ WEIGHT PRO D 1R .
Note: Preheat
the pot to
180 F. Maintain
that
temperature throughout
the process.
1. Chlorinated 120.0 Ibs 6.0%a Charge. Mix at
Plasticizer low
speed.
2. Epoxidized 100.0 lbs S.0% Charge.
Soya Oil
3. Solid Chlorinated760.0 Ibs 38.0% Charge. Turn
Paraffin ondisperser
at medium speed.
Continue mixing
until the
material becomes
fluid.
4. Carbon Bhack 94.0 Ibs 4. 7 % Charge one bag
at a time.
5. Talc 520.0 !bs 26.0 % Charge one bag
at a time.
Turn on vacuum.
Mix
with low speed
blades at
low setting and
dispersion
at medium speed
for 30
minutes.
6. Atmospheric 404.0 lbs 20.2 % Charge. Turn
Curing Resin on vacuum.
Composition* Mix at low speed
alt
blades for 15
minutes.
Moisture content
test.
7. Dibutyltin 2.0 Ibs Q,~,~ Charge. Tltrn
C>ilaurate on vacuum.
Then close vacuum.
Mix
at low speed
atl blades
for 15 minutes.
2000.0 100.0%
A preferred chlorinated plasticize°' is a 52'!o chlorine, long chain
normal paraffin (Cerechlor*S52,
ICl). A preferred epoxidized soy: oil is a high molecular weight soybean oil
epoxide (Paraplex*C:-
62, Rohm and Haas). A preferred solid chlorinated paraffin is a 70% chlorine,
long chain normal
paraffin (Chlorez*700-S, Dover <'hemical).
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WO 97/15619 PCT/US96/16960
10
yam ~~rt .r. .c
CHARGE
WEIGHT % WEIGHT PROC
Note: Preheat the pot
to
180F. Maintain that
temperature throughout
the process.
1. Chlorinated 86.0 Ibs 5.0% Charge. Mix at low
Plasticizer
speed. Save 5 Ibs for
step
9.
2. Polyisobutylene172.0 Ibs 8.6 % Charge.
3. Solid Chlorinated947.0 Ibs 47.3 % Charge one bag at a time.
Paraffin
Turn on disperser at
medium speed. Continue
mixing until the material
becomes fluid.
4. Carbon Black 17.0 lbs 1.0% Charge one bag at a time.
5. Talc 207.0 lbs 10.3 % Charge one bag at a time.
Turn on vacuum. Mix
with low speed blades
at
low setting dispersion
at
medium speed for 30
minutes.
6. Atmospheric 517.0 Ibs 27.63 % Charge. Turn on vacuum.
Curing Resin
Composition* Mix at low speed all
blades for 15 minutes.
7. Dibutyltin Dilaurate,1. 55 9.0 0.17 % Slurry with 5 Ibs of
firms
chlorinated plasticizer
from step 1. Turn on
vacuum. Then close
vacuum. Mix at low speed
all blades for 15 minutes.
2001.0 100.0%
A preferred polyisobutylene is a low molecular weight polyisobutylene
(Vistanex LM, Exxon). ..
CA 02234668 2003-04-22
II
*ATMOSp~-]FR IC CL1_R_INGIt,E~IN POSITION
COM
CHARGE
~~j=,g~, ]~~ % WEIGHT PROCEDIIRF
1. Permapoi*MS 9SU.0 Ibs 58.3% Charge. Mix at
Pol'~mer low
speed.
2. Organo Functional13.5 Ibs U.8 % Charge.
Silane ~ 1
3. Organo Functional13.5 lbs U.8 % Charge.
Silane fi~2
4. Talc ~~ 4U.t)% Charge one bag
at a time.
Turn on vacuum.
Mix to
uniformity. Moisture
content test.
1629.0 100.0% .
1'he first oganu functional silane is preferably vinyl silane, or
vinyltrimethoxysilane (A-171, OSI).
'fhe second orl;ano functional silane is preferably epoxy silane, or
glycidoxypropyltrimethoxysilane
(A-187, OSI), The two silanes are different at the organo functional end of
the molecule.
* Trade-mark
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WO 97/15619 PCT/US96/16960
12
The foregoing discussion and examples are merely meant to illustrate
particular embodiments of the invention, and are not meant to be limitations
on the
practice thereof. It is the following claims, including all equivalents, which
define
the scope of the invention.
What is claimed is:
r
