EP2909410B1

EP2909410B1 - Improved window insulation

Info

Publication number: EP2909410B1
Application number: EP13770409.4A
Authority: EP
Inventors: Filip VAN MIEGHEM; Peter Geboes
Original assignee: Soudal NV
Current assignee: Soudal NV
Priority date: 2012-08-29
Filing date: 2013-08-29
Publication date: 2023-09-27
Anticipated expiration: 2033-08-29
Also published as: RU2636015C2; RU2015110715A; FI2909410T3; PL2909410T3; ES2964282T3; PT2909410T; EP2909410A1; WO2014033231A1

Description

FIELD OF THE INVENTION

The present invention relates to the thermal insulation of windows. More particularly, the invention relates to an improvement of the thermal insulation of windows in buildings.

BACKGROUND OF THE INVENTION

The conventional energy sources are becoming increasingly scarce and difficult to produce. Nuclear energy is falling out of fashion. Renewable energy sources remain a challenge for achieving sufficient scale, sustainable economics, and maintaining consumer acceptance.
In this continuous struggle for meeting the increasing demand of consumers for energy at an affordable cost, it has become evenly important to consume energy responsibly. Energy conservation has become a prime factor in society as a whole, and of industry in particular.
The heating and/or cooling of buildings represents an important part of the global energy consumption. And as living standards continue to improve, the consumer expresses an increased desire for controlling his direct environment, at home as well as at work. But where real estate investors were building for the sale or renting out of the building to another entity as the occupant, any extra investment in energy conservation used to be scrutinized and often deleted in order to save on investment costs. The authorities, concerned and typically held responsible for the energy supply to society, have therefore started setting increasingly tight standards with respect to the energy performances of buildings, both new and existing. The European Union for instance has recently reissued in this context its Energy Performance of Buildings directive 2010/31/EC, a revision of the original directive 2002/91/EC. The Flanders region of Belgium has in 2006 adopted an energy performance directive for new and renovated buildings with minimum levels of thermal insulation, energy performance and ventilation. These requirements have been further tightened as of January 2010.
The building industry has thus been faced with an increasing need for thermal insulation. The non-transparent parts of the building envelope, i.e. the walls, floors and ceilings, may most readily be provided with extra layers of thermal insulation, even in a retrofit scenario. The windows and other transparent panes, however, have traditionally been the most important contributors to the heat exchange of a building with its surroundings, and are also the most difficult to improve.
Insulated glazing, i.e. double or even triple glazing separated by an air or other gas filled space, has become the standard for several decades in most regions now. Because of its higher weight, triple glazing may be too heavy in particular circumstances, especially with moving frames. Filling gasses are selected for their lower thermal conductivity as compared to air, and/or for their higher viscosity which reduces convection. Further gains may be provided by applying a thin metal layer onto the glass, usually silver, which is transparent for most visible light but effective in reflecting primarily the longer wavelength infrared (IR) heat radiation from inside the building towards the outside. Modern "HR++" glazing, comprising two glass panes separated by 15 mm of argon filled space and including such a hardly noticeable metal layer, may achieve a U_g-value (= heat transmission of the glass) according to standard EN 1279 of 1.1 W m^-2K^-1. Triple glazing with coating and gas filling may achieve a U_g-value as low as 0.5 or even 0.4 W m-²K^-1. The thermal performance of glass sections or frame materials is sometimes expressed in terms of their resistance to heat transfer, which is translated into an R-value, usually expressed in (K m²/ W) or in (h ft² °F/BTU).]
As spacers for the double glazing, originally hollow metal parts have been used, usually made out of aluminium, optionally provided with a thermal barrier. More recently, also other materials were used for the spacers, such as silicone foam. Strongly adhesive sealants are used to seal the joints between the spacers and the glass panes to prevent water migration, at the same time avoiding thermal bridges between the glass panes and the spacer. Polyisobutylene (PIB) is frequently used as the prime adhesive sealant or "primary sealant", because of its excellent air barrier properties, and also for its high UV-resistance. At the locations which are shielded from sunlight, such as by the window frame, a polysulfide or a polyurethane sealant may also be used, in which case it is called the "secondary sealant".
EP 1744002 A2 is concerned with simplifying the two step assembly method of first producing the double glazing unit filled with a noble gas and closed with the spacer and the primary and secondary sealants, followed by transporting the glass unit and fixing it with another adhesive into the window frame. EP 1744002 A2 proposes to apply the secondary sealant, selected from the standard adhesive materials known in the art for this application, after the glass unit has been positioned into the window frame, such that a single layer of adhesive is forming a strong bond between at least the spacer between the plates of the double glazing and the window frame profile. Polyurethane, in general and without any further detail, is listed as a suitable adhesive for use as the secondary sealants material.
The thermal performances of window frames have also been receiving attention. The progress in this field has however not kept pace with this of the glass, and current U_f-values (= heat transmission of the frame) according to standard EN 12412 (as tested) or EN ISO 10077-2 (as numerically calculated) are usually 0.8-0.9 W m^-2K^-1 at best. There is therefore an interest in reducing the width of the window frame for thermal performance purposes, which is aligned with a recently developing desire to reduce frame width for aesthetic reasons. The width of the window frame is however strongly imposed by its structural strength, especially with moving frames, required for carrying the glass units which are rather becoming heavier, as well as by the way of fixing the glass units inside the frames, many of which may require a significant overlap of the frame with the glass section.
Improvements in the thermal performances of the glass and/or the frame are strongly contributing factors, but what really matters is the overall performance of the entire window, i.e. when all the components are assembled and after the window has been installed. This is usually addressed by the U_W-value (= heat transmission of the window) according to standard EN ISO 10077-1. An already common target for the overall thermal performance of windows in an ideal "passive house" is to achieve an U_W-value of at most 0.8 W m^-2K^-1, which is well below the current legally prescribed maximum level of 2.2 for U_w and 1.3 for U_g.
As the thermal performances of the major individual components of a window continue to improve, the minor elements in the window assembly are gaining in importance.
One such element is the gap around the glass section, i.e. between the glass and the frame. This gap is provided in order to avoid excessive tension on the glass, which may be caused by temperature differences between different elements, such as by the different thermal expansion of the glass versus the frame material, but also by pressure differences between the outside and the inside of a building. This pressure differential may be intentional, such as with safe havens in industrial environments, or it may occur sudden and unexpected, such as with sound waves or under the pressure of strong winds.
The glass surfaces in double glazing are conventionally numbered from the outside towards the inside. The window is usually assembled by placing the surface # 1, which is facing the outside, against a rim provided as part of the window frame. A silicone sealant is usually provided for sealing the surface #1 of the glass to the window frame.
When the glass pane is installed, it is typically positioned on small pieces of positioning plastic or wood, also known as "support blocks" or "setting blocks", which are placed inside the frame, and which assure a gap below the glass unit. Further positioning aids may be added on the side of the glass unit. When the glass section has been properly positioned, a glazing bead is then attached to the frame, securing the glass section in place. Again a silicone sealant may be provided for sealing surface # 4, which is facing the inside, to the stop. The gap around the outer perimeter of the glass unit or glass section is typically left empty, i.e. filled with air. Holes may be drilled or provided in the frame or through the covering rim, especially in the bottom section, in order to allow evacuation of any water which may condense inside the gap, such that the risk for growth of fungi in the gap is reduced. The holes allow exchange of air between the gap inside the window and the window surroundings.
WO 98/19036 A1 discloses a sealing profile for double or triple glazing, produced in one piece by extrusion of a cross-linking polymer material, which acts as the spacer for the window panes but is further provided with gripping rims extending over and gripping around the edges of the glass panes. The profile forms a peripheral spacer which also holds the glass panes. The spacer part of the profile is glued to the inside of the glass panes with butyl rubber and adhesive tape. The profile is at its edge further provided with elastic rims, which upon installation of the glass unit in the window frame, form an elastic sealing between the outer surfaces of the glass unit and the window frame. This part of the profile may obviate the need for the silicone sealant between the outer glass pane surfaces and the window frame and glass bead, which saves work at the building site where the glass unit is inserted into the window frame. The profile is alleged to improve heat insulation because the glass panes are fitted in a gas and airtight manner in the peripheral spacer. As may be noticed on Figure 3 of WO 98/19036 A1 , an air gap remains between the window frame and the outer perimeter of the polymer profile.
DE 3514540 A1 discloses a window assembly using a frame profile containing thermally insulating profile connecting parts. The space between the window beads and the profile may be partially filled with a filling (54, 68), such that a free gap (56, 70) of about 20 mm deep is left open for convection inside the window frame.
This air gap between the glass section and its surrounding frame leaves things to be desired, primarily because the air may move inside that gap, hence its thermal performance is low when compared to the other elements of a window assembly and in view of its increasingly important contribution in the overall thermal performance of the window.
GB 2470580 discloses a window assembly wherein the glazing cavity between the glazing unit and the window frame is divided into two or more separate compartments by dividing means running substantially the periphery of the glazing unit, such that a barrier is provided to prevent air flow in the direction across the glazing cavity from an outside area to an inside area. The dividing means may be a flexible rubber finger of suitable height such that, when the glazing unit is moved into place, the finger deforms and wipes across the end of the glazing unit, therefore ensuring contact between both the end face of the glazing unit and the opposed spaced bottom of the glazing cavity. An alternative dividing means may be an acrylic impregnated open cell flexible polyurethane foam sealant strip similar to that used in the civil engineering industry to fill brick to brick joints. The strip is to be applied in a compressed state and the glazing unit is to be assembled to the frame before the expanding member has fully expanded. Such a foam sealant strip is pre-shaped and must be cut to the appropriate size at the location of assembly, with the result that usually some space is left between successive pieces of strip through which air may still move. The thermal insulation properties of the window assembly according to GB 2470580 may thus still be further improved.
DE 19546847 A1 is concerned with fixing the glass unit into the window frame. At the lower part of the window frame, rigid inserts 14 are placed into the groove of the frame, providing a flat horizontal surface to receive the lower side of the glass unit. The insert has passages for letting fluid pass through so that liquid may be drained via drain openings. At the upper or side parts of the window, cylindrical inserts are inserted which have a piston closing off an internal volume which may be filled through an access canal. Before the assembly, the insert leaves sufficient room with the perimeter of the glass unit such that the glass unit may be brought in place without any resistance. Subsequently the glass unit is blocked in place by injecting, through the canal and into the internal volume of the insert, a curing fluid under pressure such that the piston is pressed against the perimeter of the glass unit. The curing fluid may be a not further defined reaction mixture resulting in rigid foam, such that the access canal is at the same time also blocked off by the curing of the fluid. In this assembly, no further support blocks for the glass unit are required. DE 19546847 A1 is not concerned with insulation performance.
US 4139973 is concerned with fixing a glass sheet in the sash of a window with reduced distortions, offering a solution to the problem of distortion of images reflected from the glass sheet. The document proposes to stuff pre-fabricated elastic spacers at intervals into the space between the glass sheet and the side walls of the channel of the window sash. Alternatively the insertion of the elastic spacers may be accomplished by filling a suitable amount of a softened or liquid elastic material such as room temperature curable polyurethane sealant, a silicone sealant, or a fast-curing polysulphide-type sealant into that space at predetermined positions, and then hardening the elastic material. In a second step, a silicone sealant is filled in the space between the glass sheet and the side walls of the channel. According to US 4139973 , it is important that the channel of the sash should not be substantially completely filled with the sealing material, but an unfilled space having a predetermined volume should be left at the bottom of the channel. This unfilled space provides room for water discharge and for elastic displacement of the glass sheet, thereby reducing the stress which may occur in the glass sheet. Preferably a back-up member for the sealing material is provided between the elastic spacers, for blocking the flow of the sealing material to the bottom of the channel. The deformations may be further reduced by bonding frame members having a higher rigidity than glass sheet to the peripheral edge of the glass sheet by an adhesive, before setting the glass sheet in the sash by the already described method.
United States Patent number 6,546,692 B1 is concerned with providing large missile impact resistance in a window system, in order to comply with recent building codes, such as the South Florida Building Code, typically concerned with resistance to hurricanes and other wind loading stresses. The disclosed method provides a 3-ply safety film laminated to both surfaces #s 2 and 3 of the double glazing, backfilling the area from the bottom or outboard portion of the spacer to the edge of the glass with silicone sealant or buytal, another caulk, and providing a silicone foam tape around the glazing channel in the window frame, between the window frame and surface # 1 of the double glazing composite. The document further proposes to backfill any gap around the window pane composite with structural silicone or buytal, i.e. again an adhesive sealant, so that the silicone also fills in the bite of the frame, and finishing the assembly with installing the glazing bead. The backfill material proposed in US 6546692 B1 may further enhance the impact resistance of the window assembly, but leaves things to be desired in view of thermal performance. In addition, silicones during hardening emit a strong odour of acetic acid, which is experienced as rather unpleasant and obnoxious by the users. A further disadvantage with silicone is that in case a window pane is broken and the glass section needs to be replaced, it is difficult to cut through the silicone backfill, and evenly or even more difficult to remove it from the gap it is filling.
Windows may also need to address other concerns, and to satisfy other requirements, besides thermal performance. Acoustic insulating properties may also be important, as well as burglar prevention.
EP 1293639 A2 discloses an easy mountable burglar resistant window assembly in which the double glazing unit is pressed sideways into the frame by a cooperation of two clasping profiles around the perimeter of the double glazing unit, the second profile being inserted at the mounting site and pressing against the head surfaces around the double glazing unit. The profiles may not need to cover the entire perimeter of the double glazing unit in order to achieve their effect. The profiles may structurally improve the window assembly and improve its burglar resistance, but they do not address, nor significantly improve, the thermal performance of the overall window assembly. The profiles of EP 1293639 A2 , in particular the profile in contact with the window frame, needs to be very specifically suited and adapted to the detailed shape and structure of the window frame. The other profile also needs to be adapted to the thickness of the glazing unit. The solution proposed in EP 1293639 A2 is therefore very specific to each window frame design and glass unit thickness, and thus far from all-round.
DE 29707708 U1 discloses a window assembly wherein the need for support blocks is avoided by filling the groove in the window frame at least partially and preferably entirely with foam. As particularly suitable foams are listed polystyrene, polyisocyanurate (PIR) and polyurethane (PUR) foam. The foam material should be fast-curing and form a closed-cell foam which must provide a strong bond between the glass unit and window frame, because of the absence of the support blocks. In order to reach those properties, the PIR and PUR materials should inevitably be selected amongst the 2-component variants thereof. These however bring the drawback that they are more complex to apply, because of the more complex application equipment involving several pressure containers with different contents, usually requiring better trained and more experienced professionals. In order to bring the required structural performance, the foam must be of relative high density, consuming a high amount of material for providing only a limited volume.
Also EP 2426304 A1 has as the objective to avoid the extra process step needed for placing the support blocks, because these bring the risk of being misplaced when the glass unit is brought into place, or with applying the adhesive for gluing the glass unit into the profiled window frame. The document teaches to extend one or two adjacent glass sides of at least one of the at least two glass blades of an insulating glass unit, preferably by 2-10 mm. The document suggests to reinforce the assembly by applying an adhesive or filler on the inner face of the extended glass blade. The document is not concerned with the thermal insulation of the window frame.
There therefore remains a need for improving the thermal performance of a window assembly. A further need exists to improve the structural performance in a way which is user friendly, economic and easy to apply at the building site and suitable for all window frame designs and glass unit thicknesses, and applicable for also the less trained technicians. At the same time, the work involved in replacing a broken glass should remain acceptably low and quick, simple and straightforward.
The present invention aims to obviate or at least mitigate the above described problem and/or to provide improvements generally.

SUMMARY OF THE INVENTION

According to the invention, there is provided a use, a window frame, and a method as defined in any of the accompanying claims.
The present invention provides for the use of a polyurethane foam forming composition for filling, in a window assembly, the gap between the window frame and the outer perimeter of the glass unit of the window, the gap being situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit and which gap is assured by support blocks, whereby the foam forming composition is dispensed from a pressurized container and wherein the foam forming composition comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt %, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming.
The present invention also provides for a method according to claim 14 for assembling a window assembly according to the present invention, and a method according to claim 15 for replacing a glass unit in a window assembly according to the present invention.
The present invention further provides for a window assembly according to claim 12, comprising a window frame, a glass unit and support blocks for supporting the glass unit in the window frame, the window assembly further comprising a gap between the window frame and the outer perimeter of the glass unit, of which the gap between the window frame and the outer perimeter of the glass unit of the window, which gap is situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit, is filled with a polyurethane foam obtained from a polyurethane foam forming composition having been dispensed from a pressurized container and which foam forming composition comprised at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition has expanded not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming.
The applicants have found that the foam filling of the gap according to the present invention provides a much better thermal insulation as compared to the same air-filled gap, or as compared to most of the conventional materials proposed in the art for filling the gap. The applicants believe that this is due to a better filling of the gap because of the expansion of the foam, as well as to the small gas bubbles in the foam, which are much better thermal insulators compared to any solid material or compared to an air-filled gap. Polyurethane foam typically has a thermal conductivity (λ) of about 0.035 W m^-1K^-1, while the thermal conductivity of silicone is in the range of 0.15-0.35 W m^-1K^-1, this of silicone foams in the range of 0.12-0.17 W m^-1K^-1 and this for polyisobutylene is about 0.20 W m^-1K^-1, i.e. values which are always significantly higher.
In addition, the conventional air-filled gap is also subject to heat transfer by convection and radiation, a thermal performance drawback which is absent with the foam filling.
The foam brings the further advantage that it provides an air-tight seal, such that the risk of air leaks via the gap between the glass unit and the window frame is significantly reduced.
The windows having the foam filled gap according to the present invention are therefore capable of reaching a low U_W-value for the overall thermal performance of the window, and are able to meet building standards which most of the windows according to the state of the art are unable to meet, or which they find more difficult to meet.
The foam according to the present invention brings the additional advantage that it is also a very good acoustic insulator. The foam filling of the gap thus also contributes to an improved acoustic insulation of the window system.
Filling the gap around the glass unit with the PU foam forming composition according to the present invention, brings the additional advantage over the air-filled gap and many filling materials known in the art, that the foam has strong adhesive power, and thus brings additional structural strength and rigidity, between the glass unit and the window frame. The foam filling thus contributes to the mechanical strength of the window assembly, in particular when taking also into account a better filling of the gap compared to the non-expanding filling materials known in the art.
Another advantage of the foam forming composition according to the present invention, is that the cured foam also provides a little elasticity, sufficient to avoid cracking when the glass or the frame moves slightly relative to the other, such as during a burglar attempt, but sufficiently low in order not to impair the mechanical strength improvement which the foam filling contributes to the window assembly.
This increased mechanical strength provides an improvement of the burglar resistance, or the resistance to wind loading stresses and/or pressure differentials, of the window assembly according to the present invention when compared to most of those assemblies which are known in the art, especially as compared to the windows in which the gap is air-filled.
The increased mechanical strength brings increased rigidity of the window assembly. This allows for a reduction of the size of the window frame for the same weight of the window, hence for the same size of the window. Because the heat transmission of the glass (U_g) is typically significantly lower than this of the frame (Uf), a reduction of the frame width for the same overall window size allows for a reduction of the overall window size for the same light capture, and/or for a further improved thermal performance and light capture for the same overall window size. The smaller frame size for the same size window is also appreciated by the consumer because of the weight reduction, in particular appreciated with moving windows, and in view of the recent aesthetic trends, as explained above.
The filling of the gap with the foam forming composition according to the present invention is also more user friendly for the workers at the building site, as compared to other polymer fillings known in the art. The foam forming composition may be made available in containers pressurized for instance with propellant gasses, and may thus readily be pushed out of the container and applied into the gap by use of a handheld applicator on the container, or by using a dispenser gun to which the container is attached. Applying a foam forming composition does not require the consumer to exert any pressure of any kind. A typical foam forming composition also hardens relatively quickly, without releasing any unpleasant odours, and any excess foam formed may readily be cut away when hard. Silicone sealants, and most other polymer alternatives, on the contrary are relatively highly viscous materials at their moment of application. At the building site, the operator needs to push these viscous materials through the typically tapered nozzle screwed on the container, which requires a high yet tightly controlled force for controlling the rate at which the material flows out of the mouthpiece. It requires skill in order to achieve a proper filling of the gap. The removal of excess material is also difficult because the material remains sticky for a relatively long period and, when cured, is difficult to cut and hence to cut accurately. Some silicone sealants in addition may produce a strong odour during their hardening, such as of acetic acid, which odour may be experienced as unpleasant or even obnoxious.
The applicants have further found that the use of the foam forming composition according to the present invention also brings several advantages compared to the use of preformed and cured PU foam profiles intended for fitting in the same gap.
Firstly, the foam forming composition according to the present invention is able to fill the available gap much better, while a preformed foam profile is less adaptable to any irregularities in the gap and usually fits less well against the window frame and/or against the glass unit. There therefore remains a risk for leaving channels through which air may flow and sound may pass, lowering the thermal and acoustic insulation performance of the window.
Secondly, the foam forming composition according to the present invention may simply be extruded from a pressure container, which is much more ergonomic and easier to perform compared to cutting and fitting a preformed cured PU foam profile into the same gap.
Thirdly, the foam forming composition according to the present invention brings extra adhesion between the glass unit and the window frame, and hence extra mechanical strength, which is not provided by a preformed and cured PU foam profile in the same gap, unless this profile is glued to both the glass unit and to the window frame.
In the present invention, the foam forming composition is made available in a pressurized aerosol can, canister or container, which is adapted to permit extrusion of the foam forming composition contained in the can, such that the foam forming composition may be dispensed from the pressurized container. This brings the advantage that the composition is easy to use, needing very little or no additional tools or equipment. The pressure in the can is provided by propellants as part of the content of the can.
In the use according to the present invention, the PU foam forming composition is dispensed from a pressurized container. The composition is - as such - dispensed from the pressurized container, which is different from a 2K PU foam application as described elsewhere in this document. The PU foam forming composition in the use according to the present invention is thus dispensed from one single pressurized container, which means that the PU foam forming composition is a 1K composition or a 1.5K composition, as explained elsewhere in this document. The dispensing from a single pressurized container brings the advantage that the application is very user friendly, fairly intuitive, and may be performed by less trained and/or less experienced operators.
PU compositions selected from 1K and 1.5K compositions lead to a less dense PU foam as compared to 2K compositions. Also the minimum presence of a propellant or blowing agent, as specified in accordance to the present invention, contributes to a less dense PU foam as compared to 2K compositions. 2K compositions are curing primarily under the chemical effect of a hardener component, usually combined with at least a small amount of water in order to promote the foam formation, while the 1K composition almost exclusively, and the 1.5K compositions are mainly relying on hardening under the effect of moisture from the surrounding air and/or substrates. The curing under the effect of moisture generates CO2, which contribute further to the foam expansion and thus also to the lower density of the PU foam ultimately obtained. This brings the advantage that less raw material is used for filling up a particular gap volume, as compared to a 2K PU composition. Yet, the applicants have found that these single container PU foam compositions are able to significantly contribute to the mechanical properties of the total window assembly. The applicants however continue using support blocks or setting blocks in order to properly position the glass unit into the window frame, before applying the PU foam forming composition according to the present invention. The applicants have found that these effects of user friendliness and lower material use, in combination with the contribution to mechanical properties, are to be preferred over an alternative which uses a 2K PU foam composition and leave out the support blocks, because the effects outweigh the advantages which may be brought by the 2K alternative.
A further element of user friendliness brought by the foam filling according to the present invention is the fact that fully hardened foam may readily be cut with a knife. This brings another advantage compared to a silicone or other polymer sealant filling. When a window needs to be replaced, for instance when smashed, the foam filling may readily be cut, in order to break the adhesion of the glass around its perimeter with the frame, so that the glass, glass unit or glass pieces may easily be removed from the window frame. Most of the remaining foam material may readily be cut away, last traces not even needing to be removed, such that the window frame may quickly be ready again for accepting the new glass pane or glass unit. Silicone sealants, and other polymer sealants, are much more difficult to cut, if not rather impossible. The replacement of a broken glass in a window of which the gap is filled with a polymer sealant such as silicone is thus much more difficult and onerous.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a cross section according to a cut according to plane AA' as indicated on Figure 2, of the connection between a double glazing unit and a wooden window frame.
Figure 2 shows a plane view of a window frame in which a double glazing unit is already positioned and before the glazing beads have been installed.

DETAILED DESCRIPTION

The present invention will be described in the following with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention.
Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein.
Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein.
The term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.
In the context of the present invention, the terms glass unit and glazing unit have the same meaning and are used interchangeably.
In the context of the present invention, the gap between the window frame and the outer perimeter of the glass unit or glazing unit is the gap which is conventionally left between the outer perimeter of the glass unit or glazing unit, outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one, usually flat, glass plate which is forming the window itself. This space may also be known as the "head space" or "head space gap" of the glass unit in the window frame. Conventionally, this gap is left substantially open, apart from a few support blocks, meaning the gap is air-filled, in particular with the intention to leave a channel for fluid movement, for water drainage, and room for any differences in thermal expansion between the glass and the window material, and/or for movement of the glass relative to the window frame under the influence of pressure waves hitting the window or pressure differences between internal and external pressure of the construction comprising the window.
In the context of the present invention, the prefix "poly" is used for meaning "more than one", which when limited to integers is the same as "2 or more" or "at least 2". The term "polyol" therefore stands for a compound having at least 2 alcohol or hydroxyl (-OH) functional groups. The term "polyisocyanate" thus stands for a compound having at least 2 isocyanate (NCO or more correctly -N=C=O) functional groups.
In the context of this invention, the prefix "tri- and higher" means "3 or more" or "at least 3".
In the context of the present invention, the foam forming composition may contain NCO-terminated molecular chains as well as any derivatives thereof, such as the silane-terminated molecular chains referred to herein below.
In the present invention, the foam forming composition is made available in a pressurized aerosol can, canister or container, which is adapted to permit extrusion of the foam forming composition contained in the can, such that the foam forming composition may be dispensed from the pressurized container. This brings the advantage that the composition is easy to use, needing very little or no additional tools or equipment. The pressure in the can is preferably provided by propellants as part of the content of the can.
In an embodiment, the PU foam forming composition according to the present invention is provided in a container of at most 20 litre volume. This brings the advantage that the mixture inside the container is more readily mixed by shaking the container, which may be more conveniently performed manually when the container has a smaller volume. This feature is even more important in the case of 1.5K compositions, as compared to 1K compositions, because the 1.5K compositions require a mixing step by the ultimate consumer, shortly prior to the application of the composition. The consumer usually does not have access to shaking machines, and hence is limited to a manual step. Therefore the smaller volumes have for this consumer a particular advantage. For that purpose, the applicants prefer that the composition in the use according to the present invention is contained in a pressurised container having a volume of at most 5 litre, preferably at most 4 litre, more preferably at most 3 litre, even more preferably at most 2.5 litre, preferably at most 2.0 litre, more preferably at most 1.5 litre, even more preferably at most 1.0 litre, yet more preferably at most 0.75 litre, preferably at most 0.60 litre of volume.
The applicants prefer, in particular for industrial purposes, to provide the composition in a pressurized container or vessel of at least 10 litre content, preferably at least 15 litre content, more preferably even at least 20 litre content, and provided with a supply hose for the composition made from a material which is chemically compatible with the PU foam forming composition, in particular a material which is not susceptible to becoming brittle over time and/or in contact with the composition, and/or which is not prone to become blocked by the PU foam composition. The applicants prefer to provide a dispensing gun, provided with a nozzle which is particularly suited for filling the relatively narrow gap between the window frame and the outer perimeter of the glass unit. The applicants further prefer to use propellants which are non-flammable, whereby explosion or fire risks are avoided when applying the composition in a workshop in which electrical motors may be running which are not of the explosion-proof type. This embodiment is according to the applicants better suited for industrial use. The applicants use a composition having a particularly low expansion, namely expanding not more than 100 % in volume when comparing the volume of the ultimately PU foam with the volume of the injected foam forming composition, even more preferably at most 80% in volume, preferably at most 70%, more preferably at most 60%, even more preferably at most 50%, yet more preferably at most 40%, preferably at most 30%, more preferably at most 20% in volume, when comparing the volume of the ultimately PU foam with the volume of the injected foam forming composition.
The foam forming composition according to the present invention is preferably applied with a gun, also known as a dispensing gun. Such a gun is characterised by having its own valve for controlling the flow of the composition. This brings the advantage that the dosing of the composition may be performed with a much higher precision as compared to an application with a handheld applicator. This advantage is particularly relevant because the gap which is being filled is a relatively narrow gap. The precision possible with the gun brings the advantage that less excess composition needs to be applied in order to obtain a good filling of the gap. Another advantage is that foam forming compositions prepared for being applied with a gun are typically formulated for a lower expansion, and thus form a denser foam, which is better performing in terms of thermal and acoustic insulation, but also in terms of mechanical properties, all being properties which are sought in the context of the present invention.
The present invention relates to a foam forming composition, in particular a one component foam (OCF) forming composition. The applicants hereby prefer to use the definition of OCF which has been agreed upon by the Association of European Adhesive and Sealants Industry, more commonly known as the "Federation Européen des Industries de Colles et Adhésifs" (FEICA), and which defines OCF as the generic term to be used for moisture curing One Component Foams dispensed from pressurised containers (a.k.a. "aerosol cans") as well as self-curing two component foams dispensed from pressurized containers (a.k.a. "1.5 component foams"). Such foam forming compositions are preferably used in so-called aerosol applications, i.e. using an "aerosol can" which has been adapted for containing and dispensing the viscous and reactive content.
The foam forming composition according to the present invention is preferably moisture curing. This means that the foam forming composition, upon extrusion, is able to harden upon contact with moisture, preferably by contact with air humidity and/or with moisture obtained from the substrate upon which the composition is applied. The composition typically expands upon extrusion and forms the foam. Preferably the curing occurs after at least some foam has been formed, and more preferably the curing is also sufficiently fast in order to limit any subsequent collapse of the foam.
Preferably the foam forming composition according to the present invention comprises a prepolymer composition. The prepolymer composition may be introduced into the can or container, the container being subsequently sealed and pressurized by injection of at least part of the pressurized propellant into the closed container, upon which the contents of the container is typically subjected to motion to cause mixing of the container content. The propellant may be added either in one go, or in two or more portions. A mixture of propellants may be used. Various additives and/or fillers may also be added to the container content, preferably together with the prepolymer.
Preferably the foam forming composition according to the present invention shows good fire proof and fire retardant properties.
Fire retardant properties may be ensured by the presence of different ingredients such as halogens, in particular bromine and chlorine containing polyols and plasticizers; liquid phosphor containing ingredients, for example phosphates, phosphonates, polyols, including halogenated types; aromatic isocyanates, such as MDI and TDI and polyester polyols which show better fire resistant properties than polyether polyols. In this latter group the aromatic polyester polyols are better performing then the aliphatic types. On top, in foams with higher amounts of closed cells the usage of fluorinated hydrocarbons as propellant results in better fire retardant properties compared to propane/ butane / DME containing formulations. The applicants prefer to use fluorinated hydrocarbons which show a good greenhouse warming potential (GWP), such as the products known as HFO 1234ze or FEA 1100.
These fire proof or fire retardant properties may be obtained by the addition of expandable graphite to the foam forming composition, preferably with the use of formulations as disclosed in EP 2350178 . The fire proof properties are particularly important in case of NCO or silane terminated organic prepolymers, which may be formulated in such a way that the fire retardant properties of the foam comply with the criteria of class B2 and B1 norm according to DIN4102 or class D and E, as well as class B and C according to EN 13501-1. Conventional prepolymers may contain up to 10 or even 20 wt. % of non-reacted monomer isocyanate, which adds to the fireproof properties, due to the higher aromatic content.
The prepolymer within the context of the present invention is preferably an NCO-terminated or a silane terminated organic prepolymer. The foam forming composition of this invention may contain a mixture of several prepolymers but will usually contain one single type of prepolymer.
In one embodiment, the foam forming composition according to the present invention comprises an NCO terminated prepolymer.
The NCO terminated prepolymer may be formed via the chemical reaction of any type of poly- or mono- towards NCO reactive compound, preferably poly- or mono-hydroxyl compounds, or a mixture of two or more of them with any type of isocyanate compound in the appropriate mixing ratio. For the purpose of producing one component aerosol foam forming compositions, these poly- or mono-hydroxyl compounds are preferably polyether alcohols or polyester alcohols, which may have widely varying molecular weights and/or functionality. The isocyanates may be aliphatic or aromatic isocyanates or a mixture of two or more different isocyanates.
Suitable isocyanates for use in the present invention include polyisocyanates, in particular aliphatic, cyclo-aliphatic, arylaliphatic, aromatic poly-isocyanates. Particularly preferred are the common industrially available di- and/or poly isocyanates, which may contain urethane groups. Examples of industrially available isocyanates are those produced for example by BAYER, BASF/ELASTOGRAN, HUNTSMAN, DOW, ONGRO, YANTAI WANHUA, etc. made available under trade names like respectively Desmodur, Lupranate, Suprasec, Voranate, Ongronate, and Wannate. Chemically, the more suitable isocyanate compounds are selected from the group consisting of isophorondiisocyanate (IPDI), toluene di-isocyanate (TDI), 1,5-diisocyanatonaphthalene (NDI), tri-iso-cyanatotrimethylmethane, 1,6-diisocyanatohexane (HDI), and 2,4- or 4,4'-di-isocyanatodiphenylmethane (MDI), and mixtures thereof. The isocyanates, their isomers or derivatives (e.g. biurete and allophanate adducts) may be used as such or as a mixture of two or more compounds. Especially preferred are the aromatic diisocyanates 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates, polymethylene polyphenyl isocyanates, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and polymethylene polyphenyl isocyanates, and mixtures thereof, in particular the mixtures which are commonly addressed as Crude MDI, and which typically contain an amount of polymeric MDI (pMDI). The isocyanates may be modified as would be readily understood by those skilled in the field of polyurethane foam chemistry, so long as the selected isocyanates react with hydroxyl compounds to create a final foam product which has the desired properties obtainable with the present invention..
Suitable hydroxyl compounds for use in the present invention are polyether or polyester alcohols or a mixture of two or more of those which contain functional hydroxyl groups, known for the production of polyurethane elastomeric adhesives and sealants, rigid, semi-rigid, flexible and froth foams. The polyether/polyester polyols may also contain amine groups. Suitable polyols for use with the present invention typically have an average molecular weight of 100 to 4500 and a functionality of from 2 to 4, preferably from 2 to 3. Within the scope of this invention, it is possible to use one single type of hydroxyl compound or a mixture of two or more different hydroxyl compounds.
In another embodiment, the foam forming composition according to the present invention comprises a silane terminated prepolymer.
The silane terminated polymer may be formed via a two-step or one-step reaction process. In the two-step process, first an isocyanate terminated polymer is formed via reaction of the poly- or mono-hydroxyl compound described above, with any type of isocyanate compound in the appropriate mixing ratio, and thereafter the NCO-groups of the thus obtained polymer are caused to react with aminosilane compounds. Particularly suitable for this reaction are the so called alpha-alkoxy amino silanes, where the alkoxy group is in the alpha position with respect to the organo-functional group and which are very reactive towards water. In the one-step process, a hydroxyl compound or a mixture of two or more different hydroxyl compounds is caused to react with an isocyanato-alkoxysilane. Particularly suitable for this reaction are the so called alpha-isocyanato silanes, such as those described below.
The OH-reactive organo-functional group is preferably an -NCO group.
NCO-reactive silane components usually respond to the general formula X-(CH₂)_nSi-R³ _z(OR⁴)_3-z in which R³ represents an alkyl, cycloalkyl, alkenyl or aryl group comprising 1-10 carbon atoms, R⁴ represents an alkyl group comprising 1-2 carbon atoms or an ω-oxaalkyl alkyl group comprising 2-10 carbon atoms in total and z is 0 or 1, n = 1, 2 or 3 and X represents the OH or NCO reactive group. Most preferred are those compounds in which R⁴ is a methyl group and z is 0 or 1, thus dimethoxy and trimethoxy terminated silane compounds. The NCO-reactive group X contains an active hydrogen atom, such as an -NH₂, -NH, -SH, epoxy or -OH group. Most preferred is the alkoxy in alpha position with respect to the organo-functional group, implying that n=1. A particularly suitable NCO reactive alpha-silane is (N-Phenylaminomethyl) dimethoxysilane.
The OH-reactive silane components have the 3 4 general formula X-(CH₂)_n-Si-R³ _z(OR⁴)_3-z where the silane termination is as described in the previous paragraph. The OH-reactive organo-functional group may be a -NCO group. Most preferred is the alpha positioning of the organo-functional group with respect to the alkoxy group, implying that n=1.
Preferred one component foam forming compositions are based on organic prepolymers, typically those which are formed using the reaction of a polyol with a polyisocyanate. Reaction products of polyols and polyisocyanates are part of the family of polyurethanes.
A polyurethane (PUR or PU) is a polymer composed of a chain of organic units joined by the carbamate or urethane link. PU polymers are formed through step-growth polymerization, by reacting one or more monomers having at least two isocyanate functional groups with at least one other monomer having at least two isocyanate reactive groups, i.e. functional groups which are reactive towards the isocyanate function. The isocyanate (-N=C=O or "NCO") functional group is highly reactive and is able to react with many other chemical functional groups. In order for a functional group to be reactive to an isocyanate functional group, the group typically has at least one hydrogen atom which is reactive to an isocyanate functional group. Most frequently compounds are used which have at least two hydroxyl or alcohol groups. Where di-isocyanate molecules are reacting with other difunctional molecules, linear polymers are formed. Where at least one of the isocyanates or one of the other molecules has three or more functional groups, the polymer structure is able to cross-link and form three-dimensional structures. The structures with a low degree of cross-linking lead to the more elastic products. For adhesives on the other hand, polymer structures with ultimately a high degree of cross-linking are preferred.
The reaction of an isocyanate monomer with a second reactant may be favoured by the presence of one or more catalysts. Suitable catalysts are amine compounds, typically tertiary amines, and organometallic compounds.
Also water is reactive towards the isocyanate function, and typically plays a role in the final curing of the polymer towards the formation of an ultimately rigid structure. The final "curing" of the polyurethane polymer, which may include further chain building as well as cross-linking, is often obtained at least partly by reaction with water, such as with atmospheric moisture or with moisture present in the substrate onto which the PU formulation is applied. An isocyanate functional group may react with water followed by liberating gaseous CO₂ to form a primary amine, a functional group which is able to react at least once with more isocyanate functional groups. This mechanism thus also may lead to cross-linking in the polymer. Thanks to this mechanism a polyurethane polymer structure with residual isocyanate functionality is able to cure or harden under the influence of atmospheric moisture, and depending on mixture viscosity at the same time may even foam somewhat further, albeit to a limited extent.
In a one component system, a polyurethane foam pressure container may for instance be prepared by introducing a mixture of towards isocyanate polyfunctional reactive compounds, typically higher molecular weight polyols and more typically polyether polyols, together with a stoichiometric excess of polyfunctional isocyanates into the can and give it sufficient time and shaking to mix the can content and have it react until all isocyanate reactive functions are substantially reacted away and substantially only isocyanate functions remain available. The so-formed viscous liquid mixture in the can is usually called a "prepolymer". Propellant gasses may be added, optionally together with the reactants listed above, to provide a pressure in the can, if desired. When using liquefied gasses such as LPG-type components or dimethyl ether (DME) as the propellants, these gasses may also act as a solvent for the other components in the mixture.
The application of the polyurethane then typically consists of releasing the viscous prepolymer mixture from the pressurized can and let it cure, in a one component foam formulation (OCF) by the reaction with atmospheric moisture and optionally also with water from a wet or moist substrate. The propellant gasses, together with the liberating CO₂, may provide a foaming effect upon the expansion of the prepolymer liquid to atmospheric pressure. The addition to the mixture of a stabilizer may help as such component may act as a nucleator for starting the formation of gas bubbles, into which the propellants and the CO₂ may then migrate. An additional effect may be, by increasing the number of nucleation points during the foam formation by addition of a nucleator, that more and smaller gas bubbles form, which may improve the properties of the foam. The curing reactions further increase the viscosity of the reacting mixture, which eventually sets as a solid polyurethane. The rate of curing may be much faster than the rate at which the gasses are able to escape from the solidifying mixture, such that a solid foam structure is obtained. Alternatively, the composition may be made to collapse faster than the composition is able to cure, in which case a dense foam may be formed, or even hardly any foam structure is remaining. Within the context of the present invention, it is preferred that the foam forming composition, when released to atmospheric pressure, does form an expanding foam. It is preferred that the expansion is not too fast and/or violent, and remains limited. It is also preferred that the foam does not collapse, and thus keeps filling well the cavity in which it is introduced.
In a two component system, on the contrary, the prepolymer with its remaining isocyanate functionality is at the moment of application mixed with a second component containing a hardener, i.e. a towards isocyanate reactive polyfunctional compound, typically a low molecular weight polyol, preferably having primary alcohol functions, which is introduced from a second and separate container, and supplied under flow or ratio control to a point where this second component is mixed with the prepolymer on its way to the point of application. The result is usually a very fast curing mixture forming a high density product with high mechanical properties. Optionally a limited amount of water may be added to the polyol, which causes CO₂ to form, and in which case even less propellants may be needed in order to obtain the desired foam structure.
The acronym MDI is in the PU industry used for diphenylmethane diisocyanate, also called methyl diphenyl diisocyanate or methylene diphenyl diisocyanate, and this may include methyl or methylene diphenyl-4,4'-diisocyanate, also known as methane diphenyl-4,4'-diisocyanate, 1-isocyanato-4-[(4-isocyanatophenyl)methyl] benzene, 4,4'-diphenylmethane diisocyanate and 4,4'-methylene diphenyl diisocyanate, together with its 2,4' and 2,2' isomers, or may also be used for the 4,4'-MDI monomer as a single isomer, or for a blend of two of the three isomers, such as a mixture of the 4,4' and the 2,4' isomer. In the context of the present invention, the terms mMDI, monomeric MDI and MDI monomer are used in its broadest sense, covering all of these possible compositions of the methane diphenyl diisocyanate monomers.
In an embodiment of the present invention, the polyurethane foam forming composition contains less than 1.00 wt% of free methyl diphenyl diisocyanate (MDI) monomer, whereby the concentration is expressed relative to the total weight of the foam forming composition. This brings the advantage that the PU foam forming composition raises less concerns related to possible irritant, allergenic and/or toxic effects of the MDI free monomer. It also brings the advantage that under particular legislation, such as under recent EU legislation, the use of an R40 risk phrase on packages containing the PU foam formulation may be avoided. This same advantage is obtained when only prepolymers are used which are fully silane terminated, i.e. without any remaining free NCO groups.
In an embodiment of the present invention, the low free MDI monomer content is obtained by employing the PU foam forming composition at least partly on polyisocyanate or on a prepolymer which has a low content of MDI monomer. Various methods are known to the skilled person for obtaining low residual levels of free MDI in the formulation, thereby reducing the concerns associated with using polyurethane formulations, and where possible, at least avoiding the R40 risk phrase. Suitable disclosures may be for instance be found in WO 03/006521 , describing the use of asymmetric polyisocyanates, WO 2007/115971 , which describes the removal of a major portion of the diisocyanate molecules from the pMDI mixture before forming the prepolymer, or in WO 00/04069 , WO 2011/036018 and WO 01/014443 , describing the removal of diisocyanate monomers from the prepolymer by distillation.
In an embodiment of the present invention, the low free MDI monomer content is obtained by introducing a towards isocyanate monofunctional reactive compound in the preparation of the PU foam formulation, in particular in the preparation of the PU prepolymer composition comprised in the PU foam forming composition. A suitable disclosure may be found in WO 2013/072380 A2 . The towards isocyanate monofunctional reactive compound reacts with MDI monomer and forms MDI monomers of which at least one of the two isocyanate functional groups has been reacted with a towards isocyanate monofunctional reactive compound. In one embodiment of the present invention, the polyurethane foam forming composition contains at least 0.4 wt% total of methyl diphenyl diisocyanate monomers of which at least one of the two isocyanate functional groups has been reacted with a towards isocyanate monofunctional reactive compound, whereby the concentration is also expressed relative to the total weight of the foam forming composition.
Preferably the composition contains at least 0.5 wt% total of methyl diphenyl diisocyanate monomers of which at least one of the two isocyanate functional groups has been reacted with a towards isocyanate monofunctional reactive compound, preferably at least 1.0 wt%, more preferably at least 2.0 wt%, even more preferably at least 5.0 wt%, yet more preferably at least 7.0 wt%, preferably at least 8.0 wt%, more preferably at least 9.0 wt%, even more preferably at least 10.0 wt%, yet more preferably at least 12.0 wt%, preferably at least 15.0 wt%, more preferably at least 20 wt%, and optionally at most 62 wt%, preferably at most 60 wt%, more preferably at most 55 wt%, even more preferably at most 50 wt%, yet more preferably at most 45 wt%, preferably at most 40 wt%, more preferably at most 35 wt%, even more preferably at most 30 wt%, yet more preferably at most 25 wt%, and this on the same basis.
In another embodiment, the towards isocyanate monofunctional reactive compound is a halogenated compound, such as a halogen containing monofunctional alcohol. More preferred, the halogenated compound is a brominated compound.
In an embodiment, the towards isocyanate monofunctional reactive compound used in obtaining the composition is for more than 0%wt represented by the halogenated compound, based on the total of the towards isocyanate monofunctional reactive compounds used, preferably at least 10 %wt, more preferably at least 25%, even more preferably at least 50%, yet more preferably at least 75 % wt, and at most 100 %wt. The halogenated compounds may be used as a single component, or in mixtures of various halogenated compounds. Preferably these halogenated towards isocyanate monofunctional reactive compounds are used in combination with other fire retardants, such as those mentioned elsewhere in this document.
The applicants have found that the use of a halogenated towards isocyanate monofunctional reactive compound brings the advantage that the flame retardant properties of the foam forming composition according to the present invention, as well as those of the foam formed with the foam forming composition according to the present invention, may significantly be further enhanced and improved. The applicants have found that this effect is not limited to the composition according to the present invention, but also applies to the compositions which are disclosed in WO 2013/072380 A2 .
The applicants prefer to use as the halogenated towards isocyanate monofunctional reactive compound a brominated compound. The applicants prefer to use a brominated monofunctional alcohol. Suitable components are for instance 2,4 dibromophenol (CAS 615-58-7), pentabromophenol (CAS 608-71-9), 2,4,6-tribromophenol (CAS No.: 118-79-6), the latter also known as 1,3,5-tribromo-2-hydroxybenzene and commercially available under trade names such as Bromkal Pur 3, Bromol, Flammex 3BP, NSC 2136, FR-613 (ICL ), or Unibrom PH 73, the latter obtainable from the company Great Lakes, and tribromoneopentylalcohol (TBNPA, CAS No's 36483-57-5 or 1522-92-5), the latter also known as 2,2,2-tris(bromomethyl)-ethanol or 3-bromo-2,2-bis(bromomethyl)propanol, for instance available as Ecoflame B-513 from the company Unibrom or FR-513 from the company ICL.

Compositions which are preferred by the applicants are listed in Table 1 below, expressed in %wt, together with their results in the fire-retarding B3/2-test according to test standard DIN 4102-1 and the test EN 13501-1.

Table 1

TYPE	NAME	Ex	1	Ex 2	Ex 3
Isocyanate (pMDI)	Suprasec 5025	31.39	24.98	24.49
Monofunctional Polyol	2-ethyl-Hexanol	8.99	4.13	2.68
Monofunctional Brominated Polyol (73% Br)	FR-513	0	4.54	7.86
Difunctional Polyol	Voranol P1010	16.71	14.78	14.49
Difunctional Polyol	Voranol P400	7.66	6.59	6.45
Flame retardant (42% Cl)	Cereclor S42	8.7	0	0
Flame retardant (32.5% Cl and 9.5% P)	TCPP	0	20	19.61
Surfactant	Struksilon 8002	1.39	1.35	1.32
Catalyst	DMDEE	0.35	0.3	0.29
Blowing agents:	Propane	6.47	6.08	5.94
	Isobutane	9.02	8.49	8.3
	Dimethylether	9.32	8.76	8.57
TOTAL		100.00	100.00	100.00

Results in the Fire Retarding tests: i.e. the B2-Test according to DIN 4102-1 and the test according to EN-13501-1:

	Ex 1	Ex 2	Ex 3
Flame height (cm)	>15	> 15	12
After time (seconds)	5	12	-
Fire class according to DIN-4102-1	B3	B3	B2
Fire class according to EN-13501-1	F	F	E

According to DIN402-1 a foam is a B2-foam when the flame height doesn't surpass the 15 cm-mark within 15 seconds. For the EN-13501-1 the flame height shouldn't surpass this same 15 cm mark within 20 seconds in order to achieve the E class. When the 15 cm-mark is surpassed, the foam is by default a B3-foam or a 'F' foam respectively, no matter what the highest measured flame-height was.
In order to strengthen the adhesive forces of the ultimate PU composition with the surrounding materials, i.e. the surfaces along the perimeter of the glass unit, and the internal surfaces of the window frame, the applicants prefer to use tri- and higher functional compounds into the prepolymer of the PU foam forming composition of the present invention. This increases the cross-linking in the ultimate polyurethane layer and increases the adhesion bonding with the various surrounding substrates. In an embodiment of the present invention, the applicants prefer that the polyurethane prepolymer composition according to the present invention is at least partly based on a towards isocyanate trifunctional reactive compound.
The container according to the present invention may contain either a one component (1K), or also a so-called 1.5 component (1.5K) system.
In the case of 1K formulations, the moisture reactive groups of the dispensed prepolymer cure almost exclusively by reaction with atmospheric moisture and/or with water coming from the substrate. This reaction is usually accompanied by cross-linking and possibly an extra increase in volume.
In case of so-called 1.5-component (1.5K) systems, chemical curing is at least partly achieved by a reaction of the reactive groups of a reactive compound having free NCO functionality, usually but not necessarily a prepolymer, with a second reactive component, usually one or more amines, added water, hydroxyfunctional molecules, primarily polyols, or mixtures thereof. This curing reaction is usually faster, such that these systems are more suitable for producing a somewhat higher density foam.
With so-called 1.5 component (1.5K) foam systems the second reactive component, preferably a hydroxy or amine component or a mixture thereof, is added to the foam forming composition shortly or immediately before the composition is dispensed from its container, and preferably in such an amount that at least partial conversion of all NCO groups is achieved. Preferably the applicants provide a pressure container containing the second reactive component inside the larger pressure container containing the NCO or silane terminated reactive compound or the foam forming composition, and add the second reactive component by opening the inside pressure container and releasing the second reactive component into the larger pressure container, preferably shortly before the foam forming composition is to be dispensed and applied. Further moisture curing may then be achieved after dispensing. This 1.5 component system brings the advantage that the curing of the applied foam is significantly faster, such that the foam may be cut or trimmed more quickly after the application thereof, which is of convenience for the user, particularly for the professional user. A further advantage of the 1.5 component foam system is that the foam reaches a higher final density, which provides better mechanical properties, which contribute in reaching the desired increased burglar resistance properties, such that this foam is particularly suitable for construction purposes, and e.g. may be used for mounting window frames and doors even without needing nails, screws or bolts. Yet another advantage is that 1.5K foam shows much less expansion upon application. It is therefore easier to dose more accurately than 1K systems, which leads to less waste and after care.
In an embodiment, the foam forming composition according to the present invention, when tested according to FEICA test method TM 1010:2011, which is currently still in draft, produces a foam with a post expansion of at most 50%, preferably at most 40%, more preferably at most 30%, even more preferably at most 20%, yet more preferably at most 10% and most preferably at most 5%. The applicants prefer to keep this post expansion limited in order to produce a denser foam, with better thermal and insulation properties and a higher mechanical strength. The applicants however also prefer a minimum of post expansion, such as at least 1%, preferably at least 2% and more preferably at least 3%, because this improves the penetration of the foam forming composition in the crevices, cracks and micropores of the window frame and the glazing unit, such that the filling of the gap is more complete and the adhesion of the foam to the surroundings is higher.
In yet another embodiment, the foam forming composition according to the present invention further comprises, expressed on the same basis of the total composition, at least one and possibly all of the following:

a) the propellant or blowing agent in a total propellant concentration of at least 10 %wt, more preferably at least 15 wt%, even more preferably at least 20 wt%, yet more preferably at least 23 wt% and optionally and possibly alternatively at most 40 %wt, preferably at most 35 %wt, more preferably at most 30 %wt, yet more preferably at most 28 wt%,
b) at least one plasticizer and/or flame retardant, preferably in a total plasticizer and flame retardant concentration of at least 0.5 wt%, preferably at least 2.0 wt%, more preferably at least 5.0 wt%, preferably at least 10.0 wt%, more preferably at least 12.0 wt%, even more preferably at least 14.0 wt%, yet more preferably at least 15.0 wt% and optionally and possibly alternatively at most 30.0 wt%, preferably at most 25.0 wt%, more preferably at most 22.0 wt%, yet more preferably at most 20.0 wt%,
c) at least one foam stabilizer and/or surfactant, preferably in a total foam stabilizer and surfactant concentration of at least 0.2 wt%, preferably at least 0.5 wt%, more preferably at least 0.7 wt%, yet more preferably at least 0.9 wt%, even more preferably at least 1.0 wt%, and optionally and possibly alternatively at most 5.0 wt%, preferably at most 3.0 wt%, more preferably at most 2.0 wt%, yet more preferably at most 1.5 wt%.

The propellant brings the advantage of quickly building foam upon application, which drives the composition into all cracks, crevices, and openings of the surrounding substrates, and hence improves the penetration of the composition into those substrates, thereby increasing the adhesive bond between all elements.
The propellants or blowing agents according to the present invention are preferably selected from the group consisting of C₁-C₄ saturated hydrocarbons, preferably propane and/or n-butane and/or isobutane, dimethyl ether (DME), a fluorocarbon or a hydrofluorocarbon, preferably R152a or R134a or trans-1,3,3,3-tetrafluoropropene (also known as HFO-1234ze) or z-1,1,1,4,4,4- Hexafluoro-2butene (also known as FEA 1100), and mixtures thereof. Preferably the propellants or blowing agents are non-flammable in any concentration in a mixture with air. More preferably the propellants are selected from a fluorocarbon, a hydrofluorocarbon, and mixtures thereof. Non-flammable propellants bring the advantage that the fire risk is reduced during the use according to the present invention, as well as later during the life of the product which was obtained from the use.
The propellants are suitably available from a large number of suppliers. HFO-1234ze is a blowing agent obtainable from the company Honeywell. FEA 1100 is obtainable from Dupont.
The foam forming composition may also comprise at least one surfactant. Surfactants may provide stability to the foam's cell structure during dispensing, curing and post-expansion processes, which occur as a result of CO₂ generated by the reaction of the free isocyanate with water. A surfactant may therefore also be called and considered as being a foam stabilizer. Surfactants may further assist in the control of the open cell to closed cell ratio which, in turn, may provide dimensional stability and may affect the foaming pressure of the final cured foam. Examples of commercially available polysiloxane polyoxyalkylene surfactants, which are particularly suitable for use in the present invention, include, without limitation, those typically used in polyurethane (rigid, flexible semi-rigid) polyurethane foam applications such as those supplied by AIR PRODUCTS, EVONIK, SCHILL & SEILACHER, BYK CHEMIE, MOMENTIVE, and others. The foam stabilizer may be selected from the group consisting of dimethicone (i.e. silicone polymer) copolyol surfactants, which may be hydroxyl and/or methoxy terminated dimethicone polyols. The surfactants may be present in the composition mixture of the present invention in an amount of 0.5 to 4.0 parts by weight, preferably 1.0 to 3.0; and more preferably about 1.0 to 1.5 part by weight.
The plasticizers are preferably selected from the group consisting of phosphates or chloroparaffins, which often exhibit at the same time also flame retardant properties, but the plasticizers may also be esters, preferably diesters, such as adipates, phthalates, cyclohexanoates, preferably those of alcohols having at least 4 and preferably at least 7 carbon numbers, such as of isononyl alcohol. Suitable examples of phosphates and phosphonates are triethyl phosphate (TEP), trichloropropyl phosphate (TCCP), tripotassium phosphate (TKP), dimethyl propyl phosphonate, diphenyl cresyl phosphate, as well as chlorinated phosphates, in particular tris-(2-chloroethyl)phosphate, tris-(2-chloroisopropyl)phosphate (TCPP), tris-(1,3-dichloroisopropyl)-phosphate, tris-(2,3-dibromopropyl)phosphate and tetrakis-(2-chloroethyl)-ethylene diphosphate, and mixtures thereof. Suitable chlorinated paraffins are readily obtainable, such as Cereclor^™ S42 and others from INEOS. Also mixtures of these compounds may be used. Plasticizers such as the diesters mentioned, e.g. diisononyl adipate, may be obtained from suppliers including BASF, Evonik or ExxonMobil Chemical. Triethyl phosphate (TEP) may be obtained from the Lanxess company. Also higher molecular weight monoesters may be used, such as isononylbenzoate (INB) obtainable from Evonik. Another suitable compound may be 2,2,4-Trimethyl-1,3-Pentanediol Diisobutyrate (TXIB) obtainable from Eastman.
Other suitable flame retardants may be selected from the group of halogenated, in particularly brominated, ethers from the type "Ixol" from the company Solvay, 3,4,5,6-tetrabromo-, 2-(2-hydroxyethoxy)ethyl-2-hydroxypropyl ester), and tetrabromo phthalate ester (available under product name DP45 from the company Great Lakes). Preferred are those which do not have free hydroxyl groups, in order not to affect the amount of NCO functions present.
The foam forming composition of the present invention may also contain one or more non-liquid flame retardants, i.e. flame retardants not having a plasticizing effect. Useful non-liquid flame retardants include, without limitation, any compound with flame suppression properties and which may be dissolved or dispersed in the polyurethane foam. These include compounds such as inorganic oxides and chlorides, red phosphor, expandable graphite, and the like.
The foam forming composition according to the present invention preferably further comprises a catalyst, such as an amine catalyst, to accelerate the reaction of the compounds in the mixture containing reactive hydrogen atoms and isocyanate groups in the phase of prepolymer formation, and to accelerate the moisture curing reaction after the reaction mixture is extruded or dispensed from the container into the gap. The amine catalyst may comprise a primary, secondary or tertiary amine, with tertiary amine catalysts being particularly preferred. Examples of suitable catalysts are dimethylethanol amine (DMEA), tetramethyl imino bispropyl amine (available as Polycat^® 15 from the company Air Products), N,N-dimethyl cyclohexyl amine (DMCHA), tetraethylene diamine (Dabco/TEDA), guanidine, diphenyl guanidine, 2,4,6-tris(dimethyl amino methyl) phenol, morpholine, N-methyl morpholine, 2-ethyl-4-methyl imidazole, N,N-dimethyl piperazine, 1,8 diazabicyclo[5.4.0]undec-7-ene. Most preferably, the amine catalyst is a dimorpholine compound such as dimorpholino polyethylene glycol (PC Cat ^® 1 KSC available from the company Nitroil), 2,2'-dimorpholino diethylether (DMDEE), with 2,2'-dimorpholino diethylether being particularly preferred.
In another embodiment, the foam forming composition according to the present invention is comprising from 0.1 to 5.0 wt%, more preferably from 0.5 to 2.0 wt% of the one or more catalyst.
Other suitable catalysts comprise all known compounds which may catalyse isocyanate reactions. Examples are titanates, such as tetrabutyl titanate or tetrapropyl titanate of tetraisopropyl titanate, and mixtures thereof. Other examples are tin carboxylates, such as dibutyl tin dilaurate (DBTDL), dibutyl tin diacetate, tin octoate, tin oxide such as dibutyl tin oxide and dioctyl tin oxide, organoaluminum compounds such as aluminum tris acetyl acetonate, aluminum tris ethyl aceto acetate, and chelate compounds such as titanium tetra acetyl acetonate. Also mixtures of these compounds may be used, and may be preferred. The total concentration thereof may be in the range of 0.01 to 5 wt% of the total composition.
In another embodiment, the foam forming composition according to the present invention may further comprise a solvent, a viscosity depressant or viscosity reducer, a UV stabilizer, and mixtures thereof.
In yet another embodiment, the foam forming composition according to the present invention is chemically compatible with the secondary sealant of the glass unit, if present, and preferably also with the primary sealant of the glass unit. It is preferred that the major components of the foam forming composition are chemically compatible, and it is more preferred that also most of the minor components are chemically compatible. This brings the advantage that the risk is reduced for a deterioration of the material sealing the glass unit coming in contact with the foam forming composition, which otherwise may lead to an escape of gas from inside the glass unit, or to a loss of any vacuum existing inside.
In another embodiment, the invention involves a pressure container containing the foam forming composition according to the present invention. Such pressure container provides an easy assurance that the foam forming composition does not prematurely come in contact with moisture and would start curing prematurely. The pressure container is also very convenient for applying the foam forming composition. This may happen with a handheld method, such as the method described in WO 2012/052449 A2 . Alternatively, the foam forming composition may be applied by a method employing a dispenser gun, such as the method described in WO 2011/151295 A1 , preferably the method described in WO 2011/151296 A2 . Preferred is that any applicator or gun, such as the applicator for handheld use, is supplied together with the container.
In yet another embodiment of the present invention, the polyurethane foam forming composition is further based on at least one polyisocyanate monomer selected from the group consisting of 3-core, 4-core, 5-core phenyl isocyanate monomers, and mixtures thereof, preferably the polyurethane prepolymer composition being based on crude methyl diphenyl diisocyanate (crude MDI), which contains some amounts of polymeric (pMDI) together with the MDI monomer.
The selection of crude MDI brings the advantage that this raw material is more readily available at a more acceptable cost, such that it brings an economic advantage. It is also the raw material which is most common in the PU industry, such that the implementation of the present invention brings the least changes to an already existing and conventional production facility. The other advantage, as compared to pure MDI monomer as a starting material, is that in the starting material the pure monomeric MDI is already diluted, which makes the target of achieving the desired low concentrations of residual free methyl diphenyl diisocyanate monomer more readily achievable.
In another embodiment of the present invention, the towards isocyanate reactive polyfunctional compound used in preparing the prepolymer is selected from a polyol and a polyol mixture. The inventors prefer to use polyether polyols, usually made by the reaction of epoxides (oxiranes) with a starter compound having an active hydrogen atom. Suitable examples thereof are for instance P400 diol obtainable under the tradename Voranol P400 or other diols like Voranol P1010 or Voranol P2000, all available from the Dow Company. Also suitable are polyester polyols, usually made from the polycondensation (i.e. polyesterification) of multifunctional carboxylic acids with multifunctional hydroxyl compounds. Suitable examples are the Isoexter^® type products available from the company COIM, the Polios^® type products available from the company Purinova, the Stepanpol^® type products available from Stepan Company, and the Hoopol^® type products available from the company Synthesia.
Suitable polyols for use in the present invention are polyether or polyester polyols known for the production of polyurethane elastomeric adhesives and sealants, rigid, semi-rigid, flexible and froth foams. The polyether/polyester polyols may also contain amine groups. The polyol preferably has an average molecular weight of 400 to 4500 and a functionality, which means an average functionality in case of mixtures, most conveniently a weight average but alternatively a molar average, of from 2 to 4, preferably from 2 to 3. Preferably the foam and/or prepolymer composition of this invention contains one single polyol, although a mixture of two or more different polyols may be used as well.
In an embodiment of the present invention, the pressure container is supplied together with at least one and preferably a pair of gloves, suitable for protecting the hands of the user from direct contact with the foam forming composition before this is fully cured.
In an embodiment of the present invention, the glass unit comprises at least two glass panes, optionally three glass panes, the glass panes being separated by a spacer. The spacer keeps the glass panes apart and defines the gap between the panes of the glass unit. Suitable spacers are known in the art, and may be made of metal, preferably aluminium for its lighter weight, but also of structural foam, such as silicone foam. The spacer may be provided as a hollow profile, in particular when made from metal or aluminium. A hollow spacer may host a desiccant, in which case preferably perforations are provided towards the gap between the glass panes, in order to keep the gas or air inside the gap sufficiently dry and to avoid moisture condensing on the inside of the glass panes. Suitable desiccants are molecular sieves or silica gel and well known in the art. In case of vacuum insulated glass, the spacer is preferably sealed with solder glass, i.e. a glass frit having a reduced melting point. The space between the two glass panes of the glass unit is preferably at least 6 mm and optionally at most 20 mm. More preferably the space is at least 9 mm, even more preferably at least 12 mm or even 15 mm. Within these ranges, a wider space typically brings a better thermal insulation. The glass panes of the glass unit may have the same thickness, but preferably the exterior glass pane is thicker than the interior glass pane. This brings the advantage of a better sound insulation because of less resonance. It also reduces the weight and the thickness of the glass unit compared to a unit having the same higher glass thickness for all panes. More preferably the difference in thickness between the panes of the same glass unit is at most 1 mm. This reduces the risk for glass break due to shear effects.
In another embodiment according to the present invention, a seal is provided between the spacer and the glass panes. Preferably polyisobutyl (PIB) rubber is used as the sealing material, because of its excellent air tightness, and its good UV-resistance. PIB rubber sealants are readily available commercially, such as the product available from Tremco-Illbruck under the product name Tremco JS680. PIB rubber is a very good sealant, but is less performing as an adhesive. In order to provide better structural strength, the applicants therefore prefer to use PIB rubber as the primary sealant together with a secondary sealant. Where the seal is less exposed to UV-radiation, a polysulfide, silicone or polyurethane sealant may be used as the secondary sealant. The applicants prefer to use the polysulfide, because this provides a better migration resistance when compared to the other compounds in the list. A suitable commercial polysulfide compound is for instance Thiover available from the company Fenzi SpA, located at Tribiano in Italy. Preferably, the foam forming composition according to the present invention is compatible with the sealing materials that are used between the spacer and the glass panes, in particular with the secondary sealant.
In another embodiment according to the present invention, the gas space between the glass panes is filled with a gas selected from the group consisting of air, argon, krypton, xenon, sulphur hexafluoride, and mixtures thereof. The use of sulphur hexafluoride, even when in mixture, brings an improved acoustic insulation as compared to the alternatives listed. More preferably argon is selected as the fill gas, because of its broader availability as compared to the other gasses listed, except air. The gas space may also contain a nearly complete vacuum, preferably a vacuum of at most 50 kPa, preferably at most 10 kPa, more preferably at most 3 kPa, even more preferably at most 100 Pa, yet more preferably at most 10 Pa, preferably at most 1 Pa, more preferably at most 100 mPa. The advantage of a vacuum is that the overall weight of the glass unit may be reduced. A vacuum space also allows for a thinner space between the glass panes of the glass unit, which may be as low as 0.2-0.5 mm. This makes the vacuum space window assembly more suitable for retrofitting existing buildings which were not originally designed for insulating glass units, in particular for older buildings which were originally built with single pane glass windows. In order to resist the pressure differences with the outside environment, the glass panes of a vacuum glass unit may be kept apart with usually a high number of additional small spacers, at regular intervals spread over the glass surface. These additional small spacers are preferably made from a transparent material, such that they are typically not noticeable unless from a very short distance.
In an embodiment of the present invention, at least one of the glass panes in the glass unit is provided with a metal layer, preferably the metal layer comprising silver (Ag), optionally also zinc (Zn). The metal layer is preferably sufficiently thin to allow visible light transmission of at least 70%, preferably at least 75%. Such metal layers may bring reflection of infra-red (IR) radiation, which may further improve the thermal performance of the glass unit. The metal layer may be applied onto the glass pane by sputtering deposition under vacuum.
In an embodiment of the present invention, the window frame comprises aluminium, polyvinyl chloride (PVC), steel and/or wood. Window frames made primarily from metals, such as aluminium or steel, and are preferably provided by at least one thermal conductivity break, usually made from a polyamide, often reinforced with fibres, preferably glass fibres.
In an embodiment of the present invention, the inner surfaces of the gap are at least partially moisturised or wetted, preferably by using a water atomizing apparatus, before applying the foam forming composition into the gap. This brings the advantage of better and faster moisture curing of the foaming composition, and provides more uniform foam having a better cell structure and adhesion. Consequently it improves the thermal performance of the window assembly as well as the mechanical properties thereof. A suitable method for wetting or moisturizing the inner surfaces of the gap is by atomizing water by use of a simple plant spray apparatus, of which simple and light weight versions are known in the art and are found in most households.
In the embodiment of the window assembly according to the present invention, the window assembly comprises structural elements which are defined in the claims.
Of particular interest is that the inner surfaces of the gap according to the present invention are at least partially moisturised or wetted, preferably by using a water atomizing apparatus, before applying the foam forming composition into the gap. This brings the advantage of better and faster moisture curing of the foaming composition, and provides more uniform foam having a better cell structure, a better filling of the pores of the substrate, and hence also an improved adhesion. Consequently it improves the thermal performance of the window assembly as well as the mechanical properties thereof. The applicants have found that this feature relating to the assembly process therefore has an effect on the window assembly itself, and hence relates to a product feature which is best described by the process feature.
In an embodiment, the invention provides for a method for assembling a window frame according to the present invention, the method comprising the steps of

(a) by means of support blocks, bringing the glass unit into position within the window frame, and
(b) before or after step (a), applying a polyurethane foam forming composition which comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, the foam forming composition being dispensed from a pressurized container, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming, for filling the gap between the window frame and the outer perimeter of the glass unit, which gap is situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit, and allowing the foam forming composition to expand and substantially cure, thereby forming a foam,
(c) optionally cutting any excess foam which may extend out of the gap, for instance the foam extending beyond the thickness of the glass unit, and
(d) installing the glazing beads of the window assembly.

The method for assembling a window frame according to the present invention preferably further comprises at least one of the steps of

(e) before step (a), placing at least one, preferably at least two and more preferably four support blocks inside the window frame,
(f) before step (a) and preferably also before step (b) if step (b) precedes step (a), placing a backing rod against the window frame for engaging with the glass unit,
(g) prior to step (b), optionally wetting at least partly the inner surfaces of the window frame which are to surround the glass unit, or of the gap formed between the window frame and the outer perimeter of the glass unit,
(h) prior to step (d), placing a backing rod against the glass unit for engaging with the glazing beads, and
(i) closing off the seals between the glass unit and respectively the window frame and the glazing bead with a sealant kit or sealant profile.

The applicants have found that the glass unit may be introduced into the window frame after the foam forming composition has been applied to the window frame, i.e. while the foam forming composition is still expanding and curing. This method may be called the "wet" method because the glass unit is introduced into still wet foam. The applicants however prefer that this method is applied with the frame in a horizontal position, which is better suited for being performed in an assembly workshop as compared to in the field or at the building site. In this "wet" method no or less support blocks may possibly be used, but the applicants prefer to use support blocks. In this "wet" method, the backing rods on one side may be used as a boundary against which the foam forming composition is applied before the glass unit is introduced. This allows for a better material use and may be more readily performed when using a dispensing gun, which offers the higher precision in applying the composition. The "wet" method brings the advantage that the foam forming composition is pressed by the glass unit against the window frame, which brings the advantage that the composition is pressed into any pores in the frame and in the glass unit, which enhances primarily the structural properties or the assembly but also further enhances the insulation properties of the assembly.
The alternative "dry" method, where the glass unit is introduced into the window frame prior to applying the foam forming composition, is most appropriate for when the window frame is already in a vertical position, such as when the window frame is already installed in a building. In this "dry" method, the applicants prefer to use the support blocks.
In another embodiment, the invention provides for a method for replacing a glass unit or glazing unit in a window assembly according to the present invention, which method comprises the steps of

(a) removing the glazing beads of the window assembly
(b) cutting the foam filling the gap between the window frame and the outer perimeter of the glass unit of the window, the gap being situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit and which gap is assured by support blocks,
(c) replacing the glass unit with a new glass unit, whereby, if needed, parts of the foam filling remaining after step b) may further be cut away and/or removed before introducing the new glass unit into the window frame,
(d) optionally filling the gap between the window frame and the outer perimeter of the new glass unit which is conventionally left between the outer perimeter of the glass unit, outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate which is forming the window itself, with a foam forming composition which comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, the foam forming composition being dispensed from a pressurized container, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming, and allowing the foam forming composition to expand and substantially cure, thereby forming a foam,
(e) optionally cutting any excess foam which may extend out of the gap, beyond the thickness of the glass unit, and
(f) reinstalling the glazing beads of the window assembly, or replacing the glazing beads with new glazing beads.

The applicants have found that the cured foam filling in the gap according to the present invention may readily be cut out with a suitable knife, much easier than if the same gap was filled with any of the filling materials known in the art. Replacing the glass unit therefore becomes less tedious and/or onerous, and may hence be performed in less time and requiring less efforts.
The applicants have further found that the foam forming composition according to the present invention may also be used when, before bringing the glazing unit into position, first the support blocks are placed. The applicants have found that the support blocks which are placed along the vertical and against the upper side of the window frame may be kept for a sufficiently long time in place for positioning the glazing unit, when these support blocks are fixed with a drop of the foam forming composition according to the present invention. This avoid the need for another fixation means, and also may avoid compatibility problems of the fixation means with for instance the secondary sealant of the glazing unit.
In the methods for assembling the window assembly according to the present invention or for replacing a glass unit or glazing unit in a window assembly according to the present invention, the applicants prefer to also include at least one and more preferably all of the following steps:

before installing the glass unit or new glass unit, positioning backing rods between the window frame and the exterior facing surface of the glass unit as a spacer for the exterior sealant, the backing rods preferably being preformed profiles having a round, rectangular or square cross section and being made from a polyester or polyurethane based material, and preferably provided with an adhesive strip for gluing the backing rod to the window frame,
after installing the glass unit or new glass unit, filling the seal between the exterior facing surface of the glass unit and the window frame with an exterior sealant or sealing profile,
before installing or reinstalling the glazing beads, positioning backing rods between the interior facing surface of the glass unit as a spacer for the interior sealant, the backing rods preferably being preformed profiles having a round, rectangular or square cross section and being made from a polyester or polyurethane based material, and preferably provided with an adhesive strip for gluing the backing rod to the interior facing surface of the glass unit, and
after installing or reinstalling the glazing beads, filling the seal between the interior facing surface of the glass unit and the glazing beads with an interior sealant or sealing profile.

The applicants prefer to use the same material for the interior and exterior sealant kit or profile. A very suitable material for the sealant profile is EPDM rubber. Suitable sealants may be silicone based and preferably comply with EN ISO 11600 class G 20 LM or class G 25 LM, in which G = glass and LM = Low Modulus, and the number relates to the maximum deformation. Silane-terminated sealants may also be used, and bring the advantage to be paintable. Yet their lower UV-resistance compared to silicone strongly suggests to indeed paint the kit shortly after its application to avoid excessive exposure to UV-light.
The present invention is now further illustrated with reference to the drawings.
The cross section in Figure 1 shows a cross section of the connection between a double glazing unit and a wooden window frame, according to cutting AA' in Figure 2. In Figure 1 roman numeral I indicates the exterior side, and roman numeral II indicates the interior side of the window. Central in Figure 1 the two glass panes of the double glazing unit are kept apart with spacer 8. Primary sealant layers 9 are sealing the two sides of the spacer in contact with the glass panes. Secondary sealant 10 is providing additional structural strength to the double glazing unit. The double glass unit is sealed, on both sides where it meats the wooden window frame, with exterior sealants 1 complemented with and supported by backing rods 3. The wooden window frame 12 is provided with water collection groove 6 and water evacuation channel 7. Figure 1 further shows how the double glazing unit is resting on a support block 4, and the frame is finished, after installing the glass unit, by installing the glazing bead 11.
Figure 2 shows a plane view of a window frame 21 in which a double glazing unit 20 is already placed and before the glazing beads 11 have been installed. The glazing unit is correctly positioned by support blocks 4, typically four as shown in Figure 2, placed at prescribed locations in the gap 22 between the glass unit 20 and the window frame 21. The support blocks 4 are leaving gap 22 between the window frame 21 and the outer perimeter of the glass unit 20. The present invention proposes to fill this gap with the foam forming composition according to the present invention.
Having now fully described this invention, it will be appreciated by those skilled in the art that the invention may be performed within a wide range of parameters within what is claimed, without departing from the scope of the invention, as defined by the claims.

Claims

Use of a polyurethane foam forming composition for filling, in a window assembly, the gap between the window frame and the outer perimeter of the glass unit of the window assembly, the gap being situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit and which gap is assured by support blocks, whereby the foam forming composition is dispensed from a pressurized container and wherein the foam forming composition comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming.
The use according claim 1 wherein the foam forming composition is dispensed using a dispensing gun.
The use according to any one of the preceding claims wherein the foam forming composition is a moisture curing foam forming composition.
The use according to any one of the preceding claims wherein the polyurethane foam forming composition comprises an NCO-terminated prepolymer.
The use according to any one of preceding claims wherein the polyurethane foam forming composition comprises a silane terminated prepolymer.
The use according to any one of claims 4-5 wherein chemical curing of the foam forming composition is at least partly achieved by reaction of the reactive groups of a first reactive component comprising NCO- or silane functionality with a second reactive component.
The use according to the preceding claim wherein the second reactive component is added to the foam forming composition shortly or immediately before the composition is dispensed from its container.
The use according to the preceding claim wherein the second reactive component is added from a pressurized container within the container which contains the foam forming composition.
The use according to any one of the preceding claims wherein the glass unit comprises at least two glass panes, optionally three glass panes, the glass panes being separated by a spacer, the space between two glass panes preferably being at least 6 mm and optionally at most 20 mm, whereby the glass panes of the glass unit may have the same thickness but preferably the exterior glass pane being thicker than the interior glass pane, more preferably the difference in thickness being at most 1 mm.
The use according to claim 9 wherein a seal is provided between the spacer and the glass panes, preferably the gas space between the glass panes being filled with a gas selected preferably from the group consisting of air, argon, krypton, xenon, sulphur hexafluoride, and mixtures thereof, more preferably argon being selected as the fill gas, or the gas space contains a nearly complete vacuum, preferably a vacuum of at most 50 kPa.
The use according to any one of the preceding claims wherein the foam forming composition comprises at least one and possibly all of the following:
a) the at least one propellant or blowing agent in a total propellant concentration of at least 10 %wt, and optionally and possibly alternatively at most 40 %wt,

b) at least one plasticizer and/or flame retardant, preferably in a total plasticizer and flame retardant concentration of at least 0.5 wt%, and optionally and possibly alternatively at most 30.0 wt%, and

c) at least one foam stabilizer and/or surfactant, preferably in a total foam stabilizer and surfactant concentration of at least 0.2 wt% and optionally and possibly alternatively at most 5.0 wt%, and
whereby the concentrations are expressed relative to the total weight of the foam forming composition.
A window assembly comprising a window frame, a glass unit and support blocks for supporting the glass unit in the window frame, the window assembly further comprising a gap between the window frame and the outer perimeter of the glass unit, of which the gap between the window frame and the outer perimeter of the glass unit of the window, which gap is situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit, is filled with a polyurethane foam obtained from a polyurethane foam forming composition having been dispensed from a pressurized container and which foam forming composition comprised at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition has expanded not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming.
The window assembly according to the preceding claim wherein the window assembly further comprises at least one of the following structural features:
(i) the foam forming composition is a one component foam composition,

(ii) the foam forming composition is a moisture curing foam forming composition,

(iii) the foam forming composition comprises an NCO-terminated prepolymer,

(iv) the foam forming composition comprises less than 1.00 wt% of free methyl diphenyl diisocyanate monomer, relative to the total weight of the foam forming composition,

(v) the foam forming composition comprises a silane terminated prepolymer,

(vi) the foam forming composition, according to FEICA test method TM 1010:2011, produces a foam with a post expansion of at most 50%,

(vii) the glass unit comprises at least two glass panes, optionally three glass panes, the glass panes being separated by a spacer, the space between two glass panes preferably being at least 6 mm and optionally at most 20 mm, whereby the glass panes of the glass unit may have the same thickness but preferably the exterior glass pane being thicker than the interior glass pane, more preferably the difference in thickness being at most 1 mm, preferably wherein a seal is provided between the spacer and the glass panes, preferably the gas space between the glass panes being filled with a gas selected preferably from the group consisting of air, argon, krypton, xenon, sulphur hexafluoride, and mixtures thereof, more preferably argon being selected as the fill gas, or the gas space contains a nearly complete vacuum, preferably a vacuum of at most 50 kPa,

(viii) at least one of the glass panes in the glass unit is provided with a metal layer, preferably the metal layer comprising silver (Ag), optionally also zinc (Zn),

(ix) the window frame comprises aluminium, polyvinyl chloride (PVC), steel and/or wood,

(x) the foam forming composition comprises at least one plasticizer and/or flame retardant, preferably in a total plasticizer and flame retardant concentration of at least 0.5 wt%, and optionally and possibly alternatively at most 30.0 wt%, whereby the concentrations are expressed relative to the total weight of the foam forming composition, and

(xi) the foam forming composition comprises at least one foam stabilizer and/or surfactant, preferably in a total foam stabilizer and surfactant concentration of at least 0.2 wt% and optionally and possibly alternatively at most 5.0 wt%, whereby the concentrations are expressed relative to the total weight of the foam forming composition.
A method for assembling the window assembly according to any one of claims 12-13 comprising the steps of
(a) by means of support blocks, bringing the glass unit into position within the window frame, and

(b) before or after step (a), applying a polyurethane foam forming composition which comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, the foam forming composition being dispensed from a pressurized container, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming, for filling the gap between the window frame and the outer perimeter of the glass unit, which gap is situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit, and allowing the foam forming composition to expand and substantially cure, thereby forming a foam,

(c) optionally cutting any excess foam which may extend out of the gap, for instance the foam extending beyond the thickness of the glass unit, and

(d) installing the glazing beads of the window assembly.
A method for replacing a glass unit in a window assembly according to any one of claims 12-13, comprising the steps of
(a) removing the glazing beads of the window assembly

(b) cutting the foam filling the gap between the window frame and the outer perimeter of the glass unit of the window, the gap being situated outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate of the glass unit and which gap is assured by support blocks,

(c) replacing the glass unit with a new glass unit, whereby, if needed, parts of the foam filling remaining after step b) may further be cut away and/or removed before introducing the new glass unit into the window frame,

(d) optionally filling the gap between the window frame and the outer perimeter of the new glass unit which is conventionally left between the outer perimeter of the glass unit, outwards from the glass unit and in between the planes defined by a straight virtual extension of the outer facing and the inner facing surfaces of the at least one glass plate which is forming the window itself, with a polyurethane foam forming composition which comprises at least one propellant or blowing agent in a total propellant concentration of at least 5 wt%, the foam forming composition being dispensed from a pressurized container, wherein the foam forming composition is a 1K composition or a 1.5K composition, and wherein the foam forming composition expands not more than 100% in volume when comparing the volume of the ultimate PU foam with the volume of the injected foam forming composition before the foaming, and allowing the foam forming composition to expand and substantially cure, thereby forming a foam,

(e) optionally cutting any excess foam which may extend out of the gap, beyond the thickness of the glass unit, and

(f) reinstalling the glazing beads of the window assembly, or replacing the glazing beads with new glazing beads.