DK179586B1

DK179586B1 - A frame member, a method for making a frame member, a frame structure and use of a frame member

Info

Publication number: DK179586B1
Application number: DKPA201670806A
Authority: DK
Inventors: Melsen Michael
Original assignee: Vkr Holding A/S
Priority date: 2016-10-13
Filing date: 2016-10-13
Publication date: 2019-02-20
Also published as: DK201670806A1; EP3309340A1

Abstract

A frame member for a sash or frame structure for a window or door, said frame member comprising: a core substantially made from a foamed material having a thermal conductivity below 0.037 W/m K, wherein at least one strength imparting layer, preferably made of metal, covering at least a part of the core.

Description

A frame member, a method for making a frame member, a frame structure and use of a frame member

The present invention relates to a frame member, such as a side, a top and a bottom piece for a sash or frame structure for a window or door, said frame member comprising:

a core substantially made from a foamed material wherein at least one strength imparting layer, preferably made of metal, covering at least a part of the core and wherein the strength imparting layer has a thickness of or below 0.1 mm, preferably below 0.06 mm.

The invention further relates to a frame structure comprising a frame member, a method of providing a frame member and use of a frame member.

Traditional wooden frame or sash structures are considered aesthetically pleasing but are not very robust, particularly not when exposed to moisture, and they lack the insulating properties wanted in modern buildings.

The robustness issues have previously been solved with window frames made from polyvinylchloride (PVC), which is very widely used, while other window makers, including the applicant, have chosen to make the frames from profiles with a wooden core, typically of ply-wood, and a polyurethane (PUR) shell. Other plastic materials have also been used for the shell, but PUR is by far the most widely used, since it has suitable properties with regard to weather resistance, insulation, mouldability etc.

These frames, however, still lack sufficient insulating properties to live up to the still stricter building regulations, which are being adopted in many countries, and it has therefore been attempted to include insulating materials in the frame member.

From US2015/0096257 a frame member is described, wherein the core has one or more core members made from expanded polystyrene (EPS) and a shell of polyurethane (PUR) encasing the core.

In US 5,833,796 a thick skin or sheet is provided on an structural article such as a window frame. The core may be made of EPS. The strength imparting layer is preferably amorpheus polyester.

EP 2463472 describes a frame member in the form of a spacer for a frame structure of a glazing for a door or a window, said frame member comprises a core substantially made from a foamed material having a low thermal conductivity and two sets of strength imparting layers made of metal and covering at least a part of the core, where one of the two sets of strength imparting layers are made of high strength metal and has a thickness of or below 0.1 mm.

It is the object of the invention to provide an alternative and cheaper frame member still having good thermal insulating properties and acceptable rigidity and strength properties.

This is achieved with a foamed material having a thermal conductivity below 0.037 W/m K, and the frame member further comprises at least one strength imparting cover layer in a different material from the strength imparting layer.

This provides a frame member with sufficient structural strength and insulation properties approximately 4-5 times better than the insulation properties of wood.

Preferably the core is thermostable up to 90 degrees C, but thermostability up to 70 degrees C will be sufficient for most applications.

The core may have a density above 80 kg/m³ and/or between 80-200 kg/m³

The strength imparting layer may be provided only on selected parts of the surface, for example only covering 4/5 or ¹Λ or 1/3 of the surface, or only selected edges of the frame member. The top and the bottom of the frame member should preferably be covered due the stress imparted on these edges. The sides do not necessarily have to be completely covered. The strength imparting layer may also enclose the core completely or having only the ends free from any strength imparting layer(s). Furthermore as the frame member is likely a profiled member with projections and grooves, the strength imparting layer does not necessarily have to cover the (narrow) grooves. Often will these grooves be used for receiving gaskets or other elements and the core will therefore not be exposed to the surroundings.

Likewise in the production process it is not possible to get the strength imparting layer or strength imparting cover layer attached to the core in the narrower grooves.

Without wishing to be bound by theory, the invention is based on the recognition that the contribution of strength of the individual components of the frame member renders it possible to provide a frame member with properties corresponding to the local load and hence demand for bending, compressive and torsional strength.

The cross-sectional configuration of the frame member is bound by certain requirements. In the top section of the frame member, adapted to face the exterior, the local load will primarily be compressive stress, whereas at the bottom section, adapted to face the interior of the building, the tensile stress is predominant. The further into the core element towards the center, the tensile and the compressive stress equalizes and consequently the stress diminishes. According to the laws of statics, the moment of inertia and hence the bending stiffness increases by the power of three of the height of the element in question. Therefore, by strengthening a frame member at its periphery, by partly or completely wrapping a frame member in a strength imparting layer, a proportionally greater contribution of the strengthening material is provided to the member, than if the same material were provided in the center of the frame member.

The strength imparting cover layer may be provided only on selected parts of the surface, for example only covering 4/5 or ¹Λ or 1/3 of the surface, or only selected edges of the frame member. The top and the bottom of the frame member should preferably be covered due the stress imparted on these edges. The sides do not necessarily have to be completely covered. The strength imparting cover layer may also enclose the core completely or having only the ends free from any strength imparting cover layer. Furthermore as the frame member is likely a profiled member with projections and grooves, the strength imparting layer does not necessarily have to cover the (narrow) grooves. Often will these grooves be used for receiving gaskets or other elements and the core will therefore not be exposed to the surroundDK 179586 B1 ings.

The frame member may have a maximum deflection of 5 mm at a load of 300 Newton, preferably a maximum deflection of 5 mm at a load of 800 Newton. Further information/circumstances may be found in the description of fig. 4.

According to a preferred embodiment the material of the core comprises a material selected from the group consisting of thermostable expanded polystyrene (EPS), graphite containing expanded polystyrene, polyphenylene oxide, polyurethane (PUR), hybrid foam and biobased polymer.

These materials provide the frame with good insulation properties. The thermostable EPS offers a thermostability up to 90 degrees C and PUR offers a thermostability up to 120 degrees C. A biobased polymer such as polylactide acid (PLA) looks and behaves like polyethylene and polypropylene and has a thermostability up to 70 degrees C. Generally polymers have good shock absorption properties due to being long chained. The core may comprise nanostructures as well in order to increase the strength of the core.

According to another embodiment the strength imparting layer may be attached to the core by means of an attachment means, such as welding, rivets, and/or an adhesive. Preferably an adhesive such as glue is used but mechanical attachment means may also be used.

The adhesive may advantageously be selected from the group consisting of a reactive hot melt adhesive, preferably a polyurethane reactive hot melt adhesive. The reactive hot melt adhesive is pressure sensitive, reactive when heated and thereby able to absorb moisture. The reactive hot melt adhesive is cross-binding and thereby elastic, providing the connection between the layers with greater strength. At the top of the frame member, the frame member is subjected to a compressive stress, the adhesion of the layer with the core is important, otherwise the strength imparting layer will begin to crease.

To increase the adhesive force at least a part of the surface of the core may be a bit rough, but not uneven, when the layers have been attached to each other by means of adhesion such as a reactive hot melt adhesive.

Preferably the strength imparting layer may be selected from a group consisting of aluminium, copper, stainless steel, such as austenitic stainless steel and/or AISI Type 304 Stainless Steel. Aluminium is generally easy to work with and is available in a number of different thicknesses. Austenitic stainless steel and/or AISI Type 304 Stainless Steel has/have a considerable smaller thermal conductivity than aluminium. Where the thermal conductivity for aluminium is approximately 240 W/m K it is only 16.2 W/m K for AISI Type 304 stainless steel and thereby considerably lower. This is particularly important when it is being used for window or door frame members, where hot and cold air meet at the frame, and thereby water vapour may accumulate on the warm side of the window or door frame, which is undesirable. To compare the thermal conductivity for wood is approximately 1.2 W/m K. The strength imparting layer may comprise several layers and/or the different strength imparting layers may be made of the same and/or different materials. The strength imparting layer is preferably a film or a foil with weatherproof qualities. The strength imparting layer may also be made of other types of steel or alloys.

The strength imparting cover layer may be selected from a group consisting of: a biobased veneer, such as bamboo veneer, hemp veneer, basically any kind of wood veneer. Other materials such as fiberglass, polypropylene, polyvinylchloride or carbon fiber may also be used. The strength imparting cover layer should both act as a strengthening layer and a decorative layer, as this will be the outer most layer of the window or door frame. The strength imparting cover layer prevents the strength imparting layer from collapsing or creasing when forces are applied to the frame member. Bamboo veneer is preferred due to its chock absorption properties and it is an environmentally friendly material. Polymers are less preferred as they are thermoplastic. The strength imparting cover layer preferably has a thickness between 0.1 and 1 mm, more preferably between 0.4 and 0.7 mm.

In some embodiments the core may be provided with a primer and/or backing layer, prior to application of the strength imparting layer. In particular when the core is made of PUR, it may be advantageous to provide the core with a primer, due to its uneven surface, where maybe only a 30% contact area between the core and strength imparting layer is obtained if no primer and/or backing layer is used. If the primer and/or backing layer is used, an intimate connection between the core and the strength imparting layer is obtainable. The strength imparting layer may be provided directly on top of the primer or an intermediate backing layer may be provided on top of the primer. The backing layer is preferably a nonwoven material used for distribution of forces.

The frame member is provided with an additional receiving element, preferably embedded in the core. The receiving elements may be individual receiving elements for receiving attachment means in the form of screws or dovels placed directly where the attachment are meant to be positioned. Alternatively or additionally a plate like element, for example a laminated plate, may be sandwiched post production of the core or embedded in the core during moulding thereof.

The frame member may comprise two or more strength imparting layers depending on the choice of material for the strength imparting layers and of the strength requirement. A larger window will for example require a frame member having a greater strength.

The strength imparting layer and the strength imparting cover layer is preferably made of different materials.

The frame members may be wrapped in a wrapping device for wrapping profiles in laminates and foils, preferably provided with rolls for the different layers and divided into wrapping zones. Ideally the zones and/or rolls are easily exchangeable for an adaptable production line. This production process allows for a differentiated wrapping, because the rollers with the different layers are easily exchangeable, for example if different kinds of wrapping are required or if first a batch of small frame members requiring one strength imparting layer are run succeeded by larger frames requiring for example two strength imparting layers or a strength imparting layer of a different material.

It may also be possible to semi wrap the core. For example a layer may be provided on the side of the core adapted to face the interior side of a building, while the side of the core adapted to face the exterior side of the building may be provided with a different layer.

The frame members are preferably joined with a dove tail connection in the corners.

The hybrid foam may be a combination of metal and/or ceramic and/or fabric and/or polymer.

The foamed material is preferably a rigid material so that not only the strength imparting cover layer contributes to the rigidity of the frame member.

The frame member is preferably a profiled and/or prism shaped frame member.

Substantially made from a foamed material, should be construed as meaning that separate elements of other materials may be incorporated info the core material, for receiving screws, dovels or other attachment means.

The frame member would as such replace the traditional wooden frame members and would thus constitute the supporting structure of the window or door. In a further aspect the frame member according to the invention may thus be forming part of a frame or sash structure for a door or a window.

In another aspect the invention relates to a method of producing a frame member according to the invention, comprising the steps of conveying the core through an adhesive application device, conveying the core through a wrapping device comprising a number of wrapping zones and thereby providing the core with a strength imparting layer.

In yet another aspect the invention relates to use of a frame member according to the invention, for the production of a window or a door.

In the following, the invention will be described in further detail with reference to the drawings in which:

Fig. 1a-c is a cross section of an embodiment of a sash member at different production stages according to the invention, fig. 2a-c is a cross section of an embodiment of a frame member at different production stages according to the invention, fig. 3 is a perspective view of an embodiment of a frame structure, fig. 4 is a diagram over deflection of a seven different embodiments of frame members in relation to the load exerted upon it.

Fig. 1a shows a core 2 of a side frame member 1 before wrapping is applied. Fig. 1b shows an embodiment of a frame member 1, where a strength imparting layer 3 has been applied onto the core 2. Fig. 1c shows an embodiment of a frame member 1 where a strength imparting cover layer 4 has been applied. The frame member 1 in a figs. 1a-c have a top 5, a bottom 6 and sides 7,8. The frame member 1 comprises an EPS core 2 and a strength imparting layer 3 in the form of 0.05 mm of AISI 304 stainless steel. The strength imparting layer 3 is attached to the core by means of a reactive hot melt adhesive (not shown). On top of the strength imparting layer 3 a strength imparting cover layer 4 is provided, and likewise attached with a reactive hot melt adhesive. The strength imparting cover layer 4 consist of a layer of bamboo veneer. The core may also be made of PLA and/or the strength imparting layer made of AISI 304 stainless steel may also be thinner, such as 0.03 mm.

The strength imparting layer 3 may also be made of two layers of 0.1 mm aluminum or other materials mentioned in the application.

The different layers are all attached in the same way, i.e. with a reactive hot melt adhesive. Other types of adhesives may be used, but may not provide the same advantages. Furthermore the core 2 has a groove 9 adapted to receive a gasket or a liner. As can be seen on the figure the strength imparting layer 3 and strength imparting cover layer 4, does not connect to the core in the groove 9. This is due to the production process where the layers are applied with rollers which are wider than the groove 9.

This embodiment may also be provided with a nonwoven backing layer (not shown) before application of the strength imparting layer 3.

The frame member 1 may be provided with one or more receiving elements for receiving attachment means.

In figs. 2a-c a sash member of a frame member 1 is shown. The description of the embodiments in figs 1a-c applies to figs. 1a-c mutatis mutantis.

In figure 3 a whole frame structure 11 can be seen comprising top, bottom and side frame members 1 of a frame, each attached to each other by means of a reactive hot melt adhesive and dove tail joints. (not shown). The frame members may be attached to each other by other means for example by gluing beveled edges together.

Fig. 4 show a diagram over tests for deflection of a six different embodiments of frame members in relation to a load exerted upon it. One graph shows an interpolation based on test results and of physical properties of the material.

In the test the frame members were supported at a distance of 100 cm. The members should thus be able to hold themselves in this position without additional support.

The members were pressed 15 mm down at a speed of 10 mm/minute and 50 mm/minute in the middle between the support points. This was done on all four sides/directions. The thermal expansion coefficients were calculated in the area of 0-50 degrees C. All members were bent to a deflection of 15 mm.

The different graphs are marked A-G.

A-F are the test results and G is the interpolated result, in which the result for A has been multiplied by 2.5, due to the mechanical properties of aluminum in relation to stainless steel.

A represents an EPS core provided with a primer foil, two strength imparting layers in the form of 0.1 mm aluminum foil and a strength imparting cover layer in the form of ash veneer.

B is an EPS core provided with a primer foil.

C is an EPS core only.

D is an EPS core provided with an ash veneer.

E is an EPS core provided with a primer foil, one strength imparting layer in the form of 0.1 mm aluminum foil and a strength imparting cover layer in the form of ash veneer.

F is a wooden core.

G is the interpolated result presumably corresponding to an EPS core provided with a strength imparting layer of 0.05 mm stainless steel and a strength imparting cover layer of ash veneer.

It is clear that both the core with two layers of aluminum (A) and the core with one layer of stainless steel (G) are preferred in relation to strength of option B-D. In terms of insulation properties option A-E and G are to be preferred over F.

This indicates that it would be preferable to use a metal as a strength imparting layer, and a strength imparting cover layer preferably made of plant/bio material.

The same reference numbers apply to the same features throughout the application. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms comprising or comprises do not exclude other possible elements or steps. Also, the mentioning of references such as a or an etc. should not be construed as excluding a plurality. When referring to a frame member, it is to be construed as a sash member and/or a frame member. In general, the features of the embodiments shown and described may be combined freely and no feature should be seen as essential unless stated in the independent claims.

Claims

A frame member, such as a side, top or bottom piece for a frame or sash structure for a window or door, the frame member comprising:

A core made essentially of a foamed material, wherein at least one reinforcing layer, preferably made of metal, covers at least a part of the core and wherein the reinforcing layer has a thickness of or less than 0.1 mm, preferably less than 0, 06 mm, characterized in that the foamed material has a thermal conductivity below 0.037 W / m K and that the frame element further comprises at least one reinforcing cover layer which is in a material other than the reinforcing layer.

The frame member according to claim 1, wherein the frame member has a maximum deflection of 5 mm at a load of 300 Newtons, preferably a maximum deflection of 5 mm at a load of 800 Newtons.

The frame member according to any one of the preceding claims, wherein the material of the core comprises a material selected from the group consisting of thermostable expanded polystyrene (EPS), expanded polystyrene containing graphite, polyphenylene oxide, polyurethane, hybrid foam and bio-based polymer.

The frame member according to any one of the preceding claims, wherein the reinforcing layer is attached to the core by means of fastening means, such as welding, rivets and / or an adhesive.

The frame member of claim 4, wherein the fastener comprises a layer of adhesive selected from the group consisting of reactive hot melt adhesive, preferably reactive polyurethane hot melt adhesive.

The frame member according to any one of the preceding claims, wherein the core is thermostable up to 70 degrees C, preferably up to or above 90 degrees C.

The frame member according to any one of the preceding claims, wherein the reinforcing layer is selected from the group consisting of aluminum, copper, stainless steel, such as austenitic stainless steel and / or AISI type 304 stainless steel.

The frame member according to any one of the preceding claims, wherein the reinforcing layer is selected from the group consisting of bio-based veneers, such as bamboo veneer, hemp veneer, wood veneer, fiberglass, polypropylene, polyvinyl chloride and carbon fiber.

The frame member according to any one of the preceding claims, wherein the core is provided with a primer layer and / or support layer before application of the reinforcing layer.

The frame element according to any one of the preceding claims, wherein the frame element is provided with a further receiving element, preferably embedded in the core.

A frame structure for a door or a window, comprising at least one frame element according to any one of the preceding claims.

A method of manufacturing a frame member according to any one of claims 1-10, comprising the steps of:

guide the core through an adhesive applicator

guide the core through a wrapping device comprising a number of wrapping zones, thereby providing the core with a reinforcing layer.

Use of a frame element according to any one of claims 1-10, for the manufacture of a window or a door.