Note: Descriptions are shown in the official language in which they were submitted.
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DIMENSIONALLY STABLE SEALANT AND SPACER STRIP
AND COMPOSITE STRUCTURES COMPRISING THE SAME
Introduction
This invention relates to an improvement in structural sealants.
The invention has particular applicability to structural sealants used in
the fabrication of thermal insulating, multiple glazed structures, and will
be described with reference thereto.
Background of the Invention
In general, the procedure for assembling a multiple glazed
structure involves placing one sheet of glass over the other in a fixed,
spaced relationship, and then injecting a sealant composition into the
space between the two sheets of glass, at and along the periphery of the two
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sheets, thereby forming a sandwich structure having a
sealed air pocket.
Heretoforej the means employed for maintaining the
spacing between the sheets o~ glass was either of a
temporary, removable nature, or of a permanent nature.
Exemplary of temporary removable spacer means are those
disclosed in U.S. Patents 2,275,812 and 3,097,061. U.S.
Patents 3,758,996 and 4,113,905 show embodiments of
permanently installed spacer means. U.S. Patent 3,758,996
also teaches the concept of incorporating a desiccant
within the spacer means. The desiccant functions as a
medium upon which moisture and organic materials in the
sealed air pocket are sorbed. This prevents the moisture
from condensing on and fogging the interior surfaces of
! 15 the sheets of glass~
In practicin~ the teachings of the prior art, multiple
steps are required. Where a removable spacer means is
employea, the spacer means must be set in place, the
sealant injected, the sealant cured, and the spacer means
thereafter removed. Where a permanent spacer means is
employed, an adhesive is applied to secure the permanen~
spacer to the glass sheets, the spacer is then set in
place, and a sealant is then injected into the peripheral
channel formed between the spacer and the edges of the
sheets of glass.
These prior art practices are cumbersome, labor
intensive and expensive, and are believed to have been
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instrumental in limiting the ~abrication of energy saving,
thermal insulating multiple glazing structures to Eactory
assembly, and the installations thereof, to situations
where cost effectiveness is established by very high
energy costs.
Clearly, the prior art practices do not readily lend
themselves to on-the-job assembly, as is, for example
required in retrofitting single glazed structures to
thermal insulating multiple glazed structures. U.S.
Patent 3,573,149 describes a rather complex prior art
procedure for forming double glazed windo~s which can be
used in retrofit applications. The procédure involves the
use of a spacer member in which is embedded a resistance
wire, and to which is appended a tubular member containing
desiccant. The procedure involves cutting the
thermo-electric spacer and sealing strip to the peripheral
length of the panel with sufficient extra length to form
electrical terminals for connection to a power supply
source, unsheathing the ends of the resistance wire
passing through the strip and applying an electric
potential thereto to heat the strip until it becomes
pliable, applying the strip to the perimeter of one panel,
reapplying an electric potential to the resistance wire to
soften the strip, aligning a second panel and pressing the
panels together, again applying an electric potential to
cure the strip, and trimming off the ends of the strip.
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In addition to being a cumbersome and undoubtedly expensive procedure,
it should be noted that the thermo-electric spacer and sealing strip employed
in the patented arrangement does not provide any means for positively main-
taining a predetermined space between the panels. Indeed, the patentees state
that the glass panes are gently but firmly pressed together until the sealing
strip "shows a black vitreous effect all around.
Other references, of general interest in showing the state of the art
are U.S. Patents 2,695,430 and 3,045,297, and British Patent 605,234 all of
which show use of various rigid spacer members and separators for multiple
pane window units, luminous panels and the like.
Against this background of cumbersome, inefficient methodology, and
multicomponent materials and structures for assembling multiple glazing
structures, the present invention contributes to the art a unitary, multi-
purpose structure which functions as a sealant and spacer, and also a
desiccant, the use of which in assembling multiple glazing structures
simplifies the methodology, reduces costs and permits assembly to be conducted
on-site as a retrofit activity, or in a factory, with equal facility. More-
over, the use of the single unitary structure of the present invention
substantially reduces the labor and materials costs involved in assembling
multiple glazing structures, thereby making such installations cost effective .
against lower energy costs than is the case with more expensive prior art
materials and procedures.
Summary of the Invention
It is therefore an object of the present invention to provide an
improvement in the structural sealant art having substantial applicability
to the assembly of multiple glazing structures.
It is a further object of the invention to provide a unitary structure
which functions as a sealant and spacer, and also as a desiccallt, and which
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finds utility in the fabrication of multiple glazing structures.
Yet another object of the invention is to provide a dimensionally
stable sealant and spacer strip which includes means for positively controlling
the spacing between two glass members which are in pressure contact with the
strip.
In accordance with one aspect of the present invention there is
provided a composite structure comprising first and second glass members
having facing, generally parallel surfaces spaced generally a finite distance
from each other and unitary means located around, and in adhering contact
with, the peripheries of said surfaces for maintaining said glass members in
spaced relationship and for effecting a seal in the space between said glass
members, said unitary means consisting of elongated, deformable, continuous
sealant means and an essentially continuous, rigid spacer means embedded in
said sealant means and extending longitudinally the entire length of said
sealant means, said unitary means being disposed within and bridging the space
between said first and second glass members with said sealant means being of a
substantially common cross sectional configuration and having substantially
flat, substantially parallel, opposed surfaces in adhesive engagement with
said facing surfaces, said unitary means having sufficient strength in the
direction normal to said facing surfaces to maintain said first and second
members at a generally finite distance from each other with said spacer means
out of contact with said first and second glass members and further including
a desiccant within the matrix of the sealant means facing the space between
said glass members.
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Other objects, features, aspects and advantages of the invention
will become apparent to those skilled in the art
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from the followin~ detailed aescription which, together
with the accompanying drawings, discloses the best mode
presently contemplated for practicing the invention.
. Brief Description of the Drawinqs
Fig. 1 is a fragmentary perspective view,-with parts
in section, showing a first embodiment of the present
invention;
Fig. 2 is a fragmentary perspective view, with parts
in section, showing a second embodiment of the present
invention;
Fig. 3 is a fragmentary perspe~tive view, with parts
in section, showing a third embodiment of the present
invention; and
Fig. 4 is a fragmentary perspective view, with parts
in section, showing a fourth embodiment of the present
invention.
Description of the Preferred Embodiments
Referring now to the drawings, it will be seen that
Fig. 1 illustrates a composite structure comprising first
member 10 and second member 12 haviny facing, generally
parallel surfaces, spaced a finite distance from each
other, and means for maintaining members 10, 12 in such
~paced relationship and for effecting a seal between the
facing surfaces thereof, comprising a sealant and spacer
strip of the present invention, designated generally as 14.
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Members 10, 12 as illustrated are formed of glass.
As further illustrated in Fig. 1 sealant and spacer
strip 14 comprises elongated ribbon 16 of deformable sealant,
enveloping and having embedded therein spacer means 18 extending
longitudinally of ribbon 16.
In the embodiment illustrated, spacer means 18 takes the
form of an undulating sheet of rigid material which may convenient
ly be formed of aluminum. It will be noted that all of the sur-
faces and edges of spacer means 18 are in intimate contact with
ribbon 16.
Due to the geometry of spacer means 18 as illustrated in
Fig. 1, it is capable of resisting compressive forces exerted on
it in a plane which is normal to a plane in which the longitudinal
axis of spacer means 18 lies, and which plane is coincident with
a plane which is normal to the planes in which members 10, 12 lie.
Thus, spacer means 18 is capable of resisting compressive forces
tending to reduce the spacing between members 10, 12, and is
thereby capable of maintaining members 10, 12 a predetermined
finite distance from each other.
It will be apparent that if sealant and spacer strip 14
was rotated 90 about its own longitudina] axis, the orientation
of spacer means 18 would be such that it would not be expected
to be capable of resisting any substantial compressive forces
exerted upon it in a direction normal to the surfaces of members
10, 12. The accordian folds would be expected to collapse. In
view of this, it will be apparent that the particular embodiment
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of sealant and spacer strip illustrated in Fig. 1 requires
attention to proper orientation for the strip to be effective as
a spacer.
It has been found in practice that the orientation of
spacer means 18, even though completely embedded within ribbon
16, is discernable upon visual inspection, since the enrobing
sealant to a slight extent tends to follow the undulations of
spacer means 18.
Nevertheless, to simplify the matter of orientation, and
for another reason explained below, it is contemplated that the
surface of sealant and spacer strip 14 which is intended to lie
in a plane normal to the surfaces of members 10, 12, be provided
with an identifying indicia. Thus, all a fabricator need do
is observe that the surface of sealant and spacer strip 14
which bears the indicia, be positioned perpendicularly to a
surface of members 10, 12. This will insure that the sealant
and spacer strip is correctly oriented.
Since the invention is applied to the fabrication of multiple
panel structures of transparent material, such as glass or
plastic, the interior, vertical surface of sealant and spacer
strip 14 is visible in the completed unit. In many commercial
assemblies, this surface has a finished look since it corresponds
to the bottom outside surface of a permanently installed metal
spacer member. Where it is desired to provide an aesthetically
pleasing corresponding surface on the sealant and spacer strip
of the present invention, the previously described indicia may
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serve this dual function. Thus, the interior, vertical surface
of sealant and spacer strip 14 may be provided wi~h decorative
facing 20 which may be adhesively or cohesively applied, or
coextruded with sealant and spacer strip 14.
When facing 20 is positioned perpendicularly to the
surfaces of members 10, 12 and interiorly of their peripheral
edges, it functions both as a means for orienting spacer means
18, and as a means providing the exposed interior, vertical sur-
face of sealant and spacer strip 14 with an aesthetically pleas-
ing, decorative facing.
An additional advantage of the configuration of spacer
means 18 illustrated in Fig. 1, is that it permits sealant and
spacer strip 14 to be bent readily around corners. This
capability is particularly desirable where the sealant and
spacer strip is employed in the fabrication of a multiple panel
unit which acts as a thermal insulating barrier, e.g., a double
glazed thermal insulating window.
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In such units the air space between the two panel members
is sealed from the atmosphere. The fewer joints which are
employed in establishing the seal, the less is the risk of
failure of the seal, which fajlure is most likely to take
place at a joint. Since sealant and spacer strip 14 can
be bent around corners, a peripheral seal can be effected
with only one joint.
As previously noted~elongated ribbon 16 of deformable
sealant envelopes and completely embeds spacer means 18.
The thickness to which elongated ribbon 16 extends beyond
the surfaces and edges of spacer means 18 is not critical
as an absolute measurement, but is important in terms of
functional considerations. ~hus, the thickness of the
enveloping sealant extending beyond spacer means 18, at
least in the plane subjected to compressive forces, must
be sufficient to maintain a continuous sealing interface
under the applied compressive forces, but insufficien~ to
permit substantial distortion of the sealant ana spacer
strip under such applied compressive ~orces. There must
be enough sealant to effect a seal, but not so much as ~o
cause a disfiguring amount of "ballooning" of the sealant -
in the area bridging the surfaces of the two panel members.
For most applications, where the surfaces of the two
members being sealed are relatively smooth, the thickness
Of the enveloping sealant extending beyond the spacer
means should be on the order of 1/8". This has been found
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to be sufficient to provide a seal, without producing excessive
ballooning.
Because the surfaces of tempered glass may not be as
flat as the surfaces of untempered glass, somewhat greater
thicknesses may be required to provide tempered glass with
an adequate seal.
As previously noted, spacer means 18 may be formed of
aluminum. It may however be formed of alternative materials,
including suitably treated paper, such as waterproofed kraft
paper, plastic, and of course metals other than aluminum.
Depending upon the material used and the configuration of the
spacer means, a wide variety of fabrication methods may be
employed, including extrusion, stamping, bending, and casting
to name a few of the more common fabrication procedures.
The elongated ribbon of sealant has heretofore been
described as "deformable", and this requires a word of
explanation. The term "deformable" as used herein is intended
to characterize a sealant, whether themoplastic, thermosetting,
or thermoplastic-thermosetting, which when used in the fabrica-
tion of composite structures contemplated by this invention, isat least initially incapable of resisting the compressive forces
exerted upon it.
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Thus, the term "deformable~ is intended to
characterize a material which in an uncured state is
incapable of resist;ng compressive forces exerted upon it,
even though upon curing it is capable of resisting such
forces. Further, the term "deformable" is intenaed to
characterize a sealant which is initially incapable of
resisting the compressive forces exerted upon it, and
remains so throughout its useful life.
It will become apparent from the oregoing explanation
that the spacer means embedded in a deformable sealant in
accordance with the present invention, may serve only the
temporary function of maintaining the spacin~ between two
members, until such time as the deformable sealant is
cured to where the sealant itself is capable of resisting
the compressive forces exerted upon the sealant and spacer
strip. It will also be appreciated that the spacer means
may function permanently as the sole means for maintaining
proper spacing between two members, as in the case where
the deformable sealant, being a true thermoplastic
20 material, never becomes capable of resisting the -
compressive forces exerted upon it, at or above
temperatures at which it flows.
It will therefore be understood that a wide variety of
materia]s may be used as the deformable sealant, including
2S polysulfide polymers, urethane polymers, acrylic polymers,
and the styrene-butadiene polymers. Included among the
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latter are a class of thermoplastic resins which when below
their flow temperature, exhi~it elastic properties of vulcanized
polymers. Such resins are sold by Shell Chemical Co. under the
trademark Kraton.
Since the present invention is employed in the fabrication
of multiple glazed, transparent thermal insulating units formed
of glass or plastic, it is desirable to use a desiccant for the
reason described above. The desiccant is incorporated within
the deformable sealant matrix. A particularly suitable class
of materials for this purpose is synthetically produced crystalline
zeolites sold by Union Carbide Corporation under the name Linde
Molecular Sieves. Another desiccant which may be used is silica
gel. Combinations of different desiccants are also contemplated.
The preferred method of manufacturing the sealant and
spacer strip in accordance with the present invention is by
coextrusion. This can be accomplished with commercially avail-
able coextruding equipment which in some instances may require
minor modification. In general, a previously formed or just
formed spacer means, is fed through the center of an extrusion
die, and the deformable sealant is extruded around the spacer
means. The composite material is then fed through a sizing die
to
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obtain a sealant and spacer strip having the desired
outside dimensions and the proper thickness of enveloping
sealant extenaing beyond the spacer means. These
coextrusion techniques are well known to those having
ordinary skill in the art.
The provision of an orienting and/or decorative
facing, if accomplished ~y coextrusion, may be achieved by
the provision o~ a second coextrusion die which either
precedes or follows the sizing die. In the latter event,
a second sizing die may be employed beneficially.
Alternatively, the orienting and/or decorative facing may
be applied adhesively or cohesively as a separate
laminating process after the coextrusion of sealant and
spacer means has been sized. The settings on the sizing
dies will of course have to take into consideration the
fact that the addition of the orienting and/or decorative
facing will increase the overall dimensions of the sealant
and spacer strip.
Fig. 2 shows a second embodiment of the invention
wherein a composite structure comprises first and second
members 22, 24 having facing, generaLly parallel surfaces
spaced a finite distance from each other, and a sealant
and spacer strip, designated generally as 26, maintaining
members 22, 24 in spaced relationship and for effecting a
seal between the facing sur~aces thereof.
Sealant and spacer strip 26 comprises elonyated body
28 of deformable sealant, and spacer means 30, enveloped
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by and embedded in the sealant and extending longitudinally of
elongated body 28.
In the embodiment illustrated, spacer means 30 takes
the form of a strip of material undulated to provide a continuous
array of complementary triangular shapes. This configuration,
when compared with the spacer means in Fig. 1, provides con-
siderably more convoluted edge per unit length of spacer means.
It will be readily apparent therefore that, the strength and
thickness of the spacer means materials being equal, the embodi-
ment in Fig. 2 will support higher compressive forces than willthe embodiment in Fig. 1. However, as was the case with the
Fig. 1 embodiment, the arrangement shown in Fig. 2 can be bent
around corners, making this embodiment of sealant and spacer
strip attractive for use where hermetic seals are needed.
Fig. 3 illustrates a composite structure in accordance
with the present invention comprising first and second members
32, 34 having facing, generally parallel surfaces spaced a
finite distance from each other, and means for maïntaining members
32, 34 in spaced relationship and for effecting a seal between
the facing surfaces thereof in the form of a sealant and spacer
strip, designated generally as 36. The sealant and spacer strip
comprises elongated body 38 of deformable sealant, and spacer
means 40 enveloped by and embedded in elongated body 38.
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In the embodiment illustrated in Fig. 3, spacer means
40 has a generally X configuration, from which it will be
apparent that it has the capability of resisting
compressive forces without regard to the orientation of
the spacer means about its longitudinal axis. Thus, this
configuration obviates the need for the exercise o~
particular care in orienting the sealant and spacer strip,
as well as the need for any orienting indicia. It may
however be desirable to incorporate a decorative facing on
one surface of the strip to satisfy aesthetic requirements~
The configuration illustrated in Fig. 3 does not lend
itself to being bent around corners, and thus requires the
use of butt joints, as illustrated in the drawing.
Turning to Fig. 4, there will be seen illustrated a
co~posite structure comprising first and second members
~ 42, 44 having facing, generally parallel surfaces spaced a
- finite distance from each other, and means for maintaining
members 42, 44 in spaced relationship and for effecting a
seal between the facing surfaces thereof, which means in
the embodiment illustratea takes the form of a sealant and
spacer strip designated generally as 46.
The sealant and spacer strip comprises an elongated
body 48 of deformable sealant and spacer means 50
enveloped by and embedded in the sealant, and extending
longitudinally of elongated body 48.
Spacer means 50 has an open box structure, which does
not require special orientation as do the embodiments
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illustrated in Figs. 1 and 2. Further, due to the
comparatively massive structure of spacer means 50, it
would be expected to be capable of supporting compressive
loads far in excess of those supportable, for example, by
the corresponding spacer means illustrated in Fig. 1.
As with the embodiment illustrated in Fig. 3, spacer
means 50 does not lend itself to bein~ bent around
. corners, and thus it can be employed most advantageously
where butt joints are acceptable. .
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