Composite insulated glass assembly and method of forming same

The invention relates to a composite insulated glass assembly, comprising a pair of spaced substrates with a flexible and resilient polymeric spacing member between the substrates, at the periphery thereof. At joints in the spacer, or at corners, where small incisions may be made for ease in forming corners, and such similar discontinuities, sealing material is positioned, bonded in the space to fill any gap or opening and restore any reduction in thermal or other value of the spacer at these positions. The spacer is conveniently positioned adjacent the periphery of the assembly and is substantially free of sealing material except at the corners.

FIELD OF THE INVENTION
 This invention relates to composite insulated glass assemblies, and more
 particularly to a method of improving the integrity and effectiveness of
 the seal between spaced apart substrates in a glass assembly, and to
 assemblies having the improved seal. The invention relates in particular
 to seals formed wholly of flexible polymers having insulative qualities,
 and to glass assemblies featuring a relatively simple fabrication process.
 BACKGROUND OF THE INVENTION
 The manufacture of composite insulated glass assemblies by applying a
 spacer between spaced glass substrates at the periphery of the substrates
 is well known. The majority of commercially available spacers comprise a
 rigid metal structure, which may also incorporate an insulating polymeric
 layer. Increasingly, spacers fabricated entirely of resilient flexible
 polymeric material are used for their improved insulating and sealing
 abilities. However, after application of the spacer, there may be a
 peripherally extending gap. A major problem can occur at corners and/or at
 the joints between the adjacent ends of the spacer, and in fact at any
 position where the cross section of the spacer is reduced. This problem
 has been addressed in the past by costly and labor-intensive solutions.
 For example, metal composite spacers typically feature a butt joint at
 each corner at the intersection between adjacent spacers. The abutting
 spacers are joined by means of an insert or a mating structure. This
 arrangement is subject to eventual leakage as the window shifts, and is
 labor-intensive to assemble. In a resilient flexible spacer, to provide
 for a relatively sharp corner at the window corners, the spacer can form
 separate lengths that join at one or more corners. Alternatively, the
 spacer may be cut partway through to permit the spacer to describe a sharp
 bend.
 As is well known, any discontinuity in the spacer creates significant
 energy losses and results in a weak spot through which moisture can leak.
 Previously, it has been proposed that taping be used or alternatively
 simply applying a filler material which is not bonded to the spacer.
 A further limitation of the prior art resides in the position of the spacer
 relative to the periphery of the glass substrates. Conventional polymeric
 spacers comprise a generally unitary body and it is difficult to maintain
 a gas impermeable seal between the spacer and the glass substrates.
 Conventionally, the seal is improved by maintaining a space between the
 periphery of the spacer and the periphery of the glass substrates, and
 applying a substantially impermeable backspace material within this gap,
 about the entire periphery of the assembly. Accordingly, it is desirable
 to provide a method for fabricating an assembly with a flexible polymeric,
 insulating spacer that eliminates the need to backfill the entire
 periphery of the glass assembly. This may be accomplished if the spacer
 includes an at least partial discontinuity at the corners, thus permitting
 a relatively sharp bend of the spacer and positioning of the spacer
 substantially adjacent to the periphery of the glass substrates. The
 discontinuity may be introduced if specific steps are taken to ensure that
 the thermal integrity of the spacer is not compromised at the
 discontinuity. As well, an improved spacer may be used in an assembly,
 wherein the spacer incorporates a substantially gas-impermeable vapour
 barrier membrane and is characterized by an improved seal. The use of such
 a spacer, permits the spacer to be positioned substantially adjacent to
 the periphery of the glass thus substantially eliminating the need to
 backfill about the entire periphery of the assembly.
 SUMMARY OF THE INVENTION
 It is a prime objective of the present invention to provide a method of
 positioning a sealant material capable of chemically fusing with the
 spacer material, at positions where the cross section of the spacer is
 reduced, or there exists a gap between spacer segments, and to provide
 assemblies embodying sealant material chemically fused to the spacer
 material.
 A further object is to provide a method of assembling an insulating glass
 assembly featuring a polymeric insulating spacer whereby backfill between
 the periphery of the spacer and the periphery of the substrates is
 required only partway around the periphery of the structure.
 In one aspect, the present invention comprises a method of forming an
 insulated glass assembly including a pair of substrates with corners,
 comprising the steps of:
 positioning a continuous length of flexible insulating polymeric spacer
 between the substrates about the periphery of the substrates, said spacer
 defined by an exterior face and an interior face;
 wherein the spacer is characterized by at least one at least partial
 discontinuity adjacent at least one corner;
 providing a sealant material having a melting point lower than a melting
 point of the spacer, the sealant comprising a material chemically
 compatible with the spacer and capable of fusing therewith; and
 introducing melted sealant material into contact with the spacer at corner
 substantially filling the discontinuity to form a generally integral one
 piece fused gas impervious junction between the spacer and the sealant
 material to restore the coefficient of thermal conductivity of the corner
 portions to substantially equal or exceed the coefficient of thermal
 conductivity of the continuous length of the spacer material. The spacer
 may be incised to create a Vee-shaped opening facing the exterior of the
 assembly at the corner of the assembly.
 Conveniently, the spacer comprises a multicomponent structure featuring a
 first layer comprising a resilient insulating material and a second layer
 comprising a flexible substantially gas impervious layer. The spacer is
 positioned on the substrates such that the first layer faces the perimeter
 of the assembly and the second layer faces the interior of the assembly,
 with the discontinuity extending substantially through the first layer but
 not into the second layer.
 Further, the spacer may remain substantially free from contact with the
 sealant except at one or more corners, where the sealant is applied to
 fill in discontinuities within the spacer.
 In another aspect, the invention comprises a composite insulated glass
 assembly having corners and corner angles and comprising:
 a pair of glass substrates in spaced relation, each defined by corners and
 an outer edge at the perimeter thereof;
 an insulating spacer body between and spacing the substrates, the spacer
 body featuring an at least partial discontinuity therein generally
 adjacent at least one of said corners; and sealant material within said
 discontinuity in contact with and bonded to the spacer body. The spacer
 body is substantially free from contact with the sealant material except
 at the corners of the assembly.
 It will be noted that the term "glass" as used herein includes substitutes
 such as Plexiglass.TM..
 The invention will be fully understood by the description of certain
 embodiments, in conjunction with the accompanying drawings.

DETAILED DESCRIPTION
 Referring now to FIG. 1, shown is an insulated glass assembly, broadly
 denoted by numeral 10. The assembly 10 includes a pair of spaced apart
 glass substrates 12 and 14 with a typical insulating polymeric spacer
 spacing substrates 12 and 14, positioned about the periphery of the
 assembly 10 at a position substantially adjacent the periphery of the
 glass substrates. The spacer in this version comprises a composite,
 consisting of an inner layer 40 formed from a resilient flexible cellular
 material, a vapour barrier which may comprise a substantially
 gas-impervious layer such as a membrane 42 and an outer layer 44 formed
 from a resilient cellular material. The cellular compound or compounds
 that comprise the components are flexible and preferably resilient. One or
 more of the components may comprise a foamed polymeric compound. Where the
 spacer is bent about a corner, a slit is cut into the spacer, extending
 from the outer layer 44 inwardly towards the membrane 42. The membrane 42
 remains intact. The slit thus forms a pie-shaped opening when extended
 around the corner, with the apex pointing inwardly towards the interior of
 the assembly 10 and the wide side opening to the periphery of the
 assembly.
 FIG. 1(a) illustrates an alternative version wherein the spacer body
 comprises a unitary member 16' formed from a resilient flexible cellular
 material.
 FIG. 2 illustrates, in a sectional view parallel to the plane of the
 substrates, two adjacent portions of spacer 16 where each section 16 meets
 at a juncture or gap 20 where the spacer is discontinuous at the point of
 intersection of two adjacent sections 16(a) and (b) meeting at a corner of
 the spacer assembly. The intersecting sections are mitred, in effect
 producing a butt joint, and the adjacent sections 16 substantially
 intersect at the terminal corner of the insulated assembly. As is well
 known in this art, any point where there is a discontinuity in the length
 of spacer 16 results in significant energy losses and effectively creates
 a weak spot in the assembly through which moisture and thermal energy can
 leak to be transmitted. This has ramifications in terms of lowering the
 useable lifespan of the assembly and contributes to the "fogging" or white
 clouding on the glass substrates.
 In order to alleviate this, it has been found that if the adjacent sections
 16 at the gap 20 can be fused or chemically bonded together, the results
 are quite dramatic in terms of restoring the thermal integrity of length
 of spacer 16 effectively to that of a continuous length. This is achieved
 since the chemical bond effectively fuses the two adjacent sections
 together at the junction 20 to restore the integrity of the seal to the
 point that the thermal properties are effectively the same as that which
 would be encountered if the seal were integral and one piece about the
 entire periphery of the assembly 10. In FIG. 2, a sealant 22 is positioned
 between the adjacent ends of the spacer 16.
 Preferably, the spacer 16 will include at least one polymer capable of
 bonding with a suitable polymeric sealant. As one example, the spacer may
 be composed of polysilicones, EPDM, polyurethanes, among a host of other
 materials known in this art to provide superior insulation quality. In
 terms of the sealant, any of the known sealants capable of chemically
 bonding with the polymeric material of the spacer 16 can be selected.
 Suitable sealants are well documented in the prior art and will be readily
 apparent to those skilled in the art.
 In the event that sealants are chosen which require heat energy to induce
 fusion between adjacent sections of spacer 16 and sealant material 22, the
 assembly may be exposed to ultraviolet light, infrared heat or simply
 convective heat in order to induce the fusion between the sealant 22 and
 the adjacent sections of spacer 16.
 Where the polymeric spacer material content and the sealant are not
 conducive to heat bonding with one another, additives may be included in
 the sealant to induce chemical fusion without the input of any extraneous
 energy.
 FIG. 3 is an enlarged view showing the spacer material having been incised
 or slit at a corner portion to provide a generally triangular gap 20 where
 flexed. The angle formed by the sides of the gap approximately equals the
 corner angle of the assembly. Thus, in a conventional rectangular
 assembly, the angle approximates 90.degree.. The spacer remains intact and
 in one piece towards the interior of the assembly, but is discontinuous at
 the exterior of the assembly as shown. Conveniently, the intact portion of
 spacer may include a gas-impermeable membrane, thus maintaining the seal
 integrity against gas leakage. In this manner, the spacer 16 remains at
 least partially integral towards the interior of the assembly, but is slit
 to accommodate flexing about the corner portions of the window assembly.
 It will be understood that the spacer 16 can be similarly slit in order to
 bend the spacer 16 about a remain corners of the assembly. In this
 arrangement, sealant material 22 is injected into the generally triangular
 gap 20 in order to fusibly connect the adjacent sections of spacer 16 thus
 restoring the thermal properties to substantially the same as a completely
 intact section of spacer. At the terminal corner (not shown) where the
 spacer starts and finishes, the joint between adjacent sections can be
 similar to that illustrated in FIG. 3.
 In a further aspect of the invention, the spacer is positioned
 substantially adjacent to the perimeter of the glass panes, thus
 eliminating the step during assembly of backfilling about the entire
 spacer assembly. In this version, the spacer comprises a flexible
 polymeric compound structure, featuring a gas-impermeable membrane
 adjacent to a first of the assembly, which when the spacer is installed
 faces inwardly towards the interior of the window assembly. Triangular
 incisions within the spacer define sharp corners, with the incision
 leaving the membrane intact as described above. The combination of the
 impermeable membrane and the corners sealant material permits the
 fabrication of a window assembly that does not require backfilling about
 the entire periphery of the spacer to provide additional sealant or
 insulation.
 FIG. 4 illustrates an assembly wherein all four corners feature a
 peripheral slitting of the seal and corner sealant according to the
 present invention, with the spacer extending substantially to the edges of
 the assembly. As shown, the spacer is substantially free from contact with
 the sealant except at the corners, where the sealant material fills in the
 corner discontinuities within the spacer.
 In order to apply the spacer and sealant material, any of the known
 automation systems or gunning arrangements can be employed.
 By practising the present invention disclosed herein, significant results
 in terms of restoring the thermal conductivity of the corner portions or
 sections of abutting or adjacent spacer sections have been found to be
 restored to substantially the same conductivity of an uninterrupted length
 of sealant material.
 This is in marked contrast to what the prior art has previously proposed
 where corner portions were simply taped or sealant material injected which
 did not facilitate bonding between the sections, but rather simply
 constituted filler material in order to remove the gap in the length of
 the spacer material around the periphery of the assembly.
 As indicated above, suitable sealants and spacer material polymeric content
 will be readily apparent to those skilled in the art. This is equally true
 of the gunning or filling techniques and the means, where required, to
 induce fusion between adjacent sections of spacers 16. Typically, one of
 the more preferred systems is to provide a sealant material 22 having a
 melting point lower than that of the polymeric of which the spacer 16 is
 made such that there is no detrimental effect to the spacer 16 but rather
 only a melting or lowering of viscosity of the sealant material such that
 it is capable of fusible interaction with the spacer 16.
 Although embodiments of the invention have been described above, it is not
 limited thereto and it will be apparent to those skilled in the art that
 numerous modifications form part of the present invention insofar as they
 do not depart from the spirit, nature land scope of the claimed and
 described invention.